Edgar Filing: AETHER SYSTEMS INC

AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON MAY 1, 2001.

REGISTRATION NO. 333-56154
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549
----------------------
AMENDMENT NO. 1
TO
FORM S-3/A
REGISTRATION STATEMENT UNDER THE
SECURITIES ACT OF 1933
----------------------

AETHER SYSTEMS, INC.
(Exact Name of Registrant as Specified in Its Charter)

DELAWARE 52-2186634
(State or Other Jurisdiction (I.R.S. Employer
of Incorporation or Organization) Identification No.)

----------------------

11460 CRONRIDGE DRIVE
OWINGS MILLS, MARYLAND 21117
(410) 654-6400
(Address, Including Zip Code, and Telephone Number, Including Area Code, of
Registrant's Principal Executive Offices)
----------------------

DAVID S. OROS
CHAIRMAN AND CHIEF EXECUTIVE OFFICER
11460 CRONRIDGE DRIVE
OWINGS MILLS, MARYLAND 21117
(410) 654-6400
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code,
of Agent for Service)
----------------------
with a copy to:

MARK A. DEWIRE, ESQ.
ROGER J. PATTERSON, ESQ.
WILMER, CUTLER & PICKERING
2445 M STREET, N.W.
WASHINGTON, D.C. 20037
(202) 663-6000
----------------------

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after the effective date of this Registration Statement.

If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. [ ]

If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, check the following box. [X]

If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. [ ]

If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [ ]

If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. [ ]

----------------------

THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THIS REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
2

PROSPECTUS

----------

3,023,560 SHARES

[AETHER LOGO]

COMMON STOCK

----------------------

The stockholders of Aether Systems, Inc. named in this prospectus are
offering and selling up to 3,023,560 shares of Aether's common stock. The
selling stockholders obtained their shares in connection with our acquisitions
of Cerulean Technology, Inc., Riverbed Technologies, Inc. or RTS Wireless, Inc.
We will receive none of the proceeds from the sale of shares of common stock by
the selling stockholders. We have agreed to bear the expenses of registration of
the shares in this prospectus.

The selling stockholders may offer their shares through public or
private transactions, on or off the Nasdaq National Market at prevailing market
prices or at privately negotiated prices. They may make sales directly to
purchasers or to or through brokers, agents, dealers or underwriters. The
selling stockholders will bear all commissions, and other compensation paid to
brokers in connection with the sale of their shares.

Our shares are traded on the Nasdaq National Market under the symbol
"AETH." On April 30, 2001, the closing sale price of shares of our common stock
was $15.07 per share.

INVESTING IN THE COMMON STOCK INVOLVES RISKS THAT ARE DESCRIBED IN THE
"RISK FACTORS" SECTION BEGINNING ON PAGE 4 OF THIS PROSPECTUS.

----------------------

Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if this
prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

----------------------

The date of this prospectus is May 1, 2001.

TABLE OF CONTENTS

PAGE
----

About Aether Systems........................................ 3
Risk Factors................................................ 4
Forward-Looking Statements.................................. 5
Use of Proceeds............................................. 5
Selling Stockholders........................................ 6
Plan of Distribution........................................ 10
Legal Matters............................................... 11
Experts..................................................... 11
Where You Can Find More Information......................... 11

2
4

ABOUT AETHER SYSTEMS

Aether provides technologies that enable businesses to extend their data
and commercial transactions to wireless and mobile handheld devices. At the core
of Aether is a comprehensive family of software products, which we refer to as
our wireless technology foundation, upon which all types of wireless systems for
businesses can be built. Our wireless technology foundation includes wireless
integration, mobile data management and wireless infrastructure software
products. We add to this foundation individual technology components which
include our wireless data engineering and development services, wireless data
hosting, product fulfillment and customer support. These components can be used
separately or in various combinations to extend existing and future business
applications to any handheld device over any wireless network.

The wireless technology foundation gives businesses, systems integrators
and developers the ability to quickly create, deploy and manage wireless
solutions across multiple carrier networks and types of devices. Customers may
choose specific wireless products or services, or have Aether build and manage a
comprehensive wireless solution. In every case, Aether's flexibility to adapt to
a wide variety of systems protects businesses from "betting" on technologies in
a rapidly changing wireless environment.

Our strategy. Our strategy is to be the dominant provider in the United
States and internationally of wireless data services and systems to corporations
by using our engineering expertise, our software products, our hosted solutions
and our other resources. We believe our capabilities and experience have
established us as an early market leader in wireless data services, and a key
element of our strategy is to move quickly into new opportunities to extend our
leadership position. Our strategy also includes the following other key
elements:

- maximize licensing revenue from our mobile data and wireless software;

- win and retain contracts to develop and operate wireless data systems for
large businesses;

- extend the industries and markets to which we provide wireless data
systems and service;

- extend our services to new markets through engineering and strategic
consulting services to businesses that are exploring the implementation
of a wireless data system;

- maintain and strengthen relationships with suppliers and customers; and

- participate in non-core markets through investments and partnerships.

Other information. We are a Delaware corporation. Our principal executive
offices are located at 11460 Cronridge Drive, Owings Mills, Maryland 21117, and
our telephone number is (410) 654-6400. We maintain a Web site at
www.aethersystems.com. Information contained in our Web site does not constitute
a part of this prospectus. All references to "we," "us," "our" or "Aether" in
this prospectus mean Aether Systems, Inc. and its subsidiaries or predecessors.

3
5

RISK FACTORS

Investing in our common stock involves risks. You should carefully
consider the following risks together with the other information contained in
this prospectus and all the information incorporated by reference before
deciding to buy our common stock. A list of factors affecting our operating
results is incorporated herein by reference to our Annual Report on Form 10-K
for the year ended December 31, 2000. The risks below relate solely to this
offering.

OUR STOCK PRICE, LIKE THAT OF MANY TECHNOLOGY COMPANIES, HAS BEEN, AND MAY
CONTINUE TO BE, VOLATILE.

The market price of our common stock has been highly volatile and is likely
to continue to be highly volatile. The trading price of our common stock has
fluctuated from a high of $305 1/16 to a low of $8 7/8 in the one year prior to
the date of this prospectus. We are involved in a highly visible, rapidly
changing industry and stock prices in our and similar industries have risen and
fallen in response to a variety of factors, including:

- announcements of new wireless data communications technologies and new
providers of wireless data communications;

- acquisitions of or strategic alliances among providers of wireless data
communications;

- changes in recommendations by securities analysts regarding the results
or prospects of providers of wireless data communications; and

- changes in investor perceptions of the acceptance or profitability of
wireless data communications.

SHARES ELIGIBLE FOR FUTURE SALE BY OUR CURRENT STOCKHOLDERS MAY DEPRESS OUR
SHARE PRICE.

As of April 27, 2001, we had outstanding 40,529,594 shares of common stock.
Sales of a substantial number of our shares of common stock in the public
market -- or the expectation of such sales -- could cause the market price of
our common stock to drop. All the shares sold pursuant to this prospectus will
be, and the shares sold in our initial public offering, our offering in March
2000, our September, 2000 offering and the October 2000 shelf registration are,
freely tradable. In addition to the shares covered by this prospectus, we have
agreed to register the resale of 12,427,041 shares upon demand. An additional
12,458,375 shares (including some of the shares subject to registration rights)
are currently eligible for sale, subject to a limitation on the number of shares
that can be sold in any three-month period.

We filed a registration statement to register all shares of common stock
that were issued to our employees under our equity incentive plan and intend to
file future registration statements. Shares issued upon exercise of stock
options will be eligible for resale in the public market without restriction. As
of April 27, 2001, options and warrants to purchase 4,404,274 shares of our
common stock and 795,794 shares of restricted stock were issued and outstanding
and covered by the registration statement. In addition, warrants to purchase
893,665 additional shares were issued and outstanding on that date.

THE STOCKHOLDER AGREEMENT AMONG OUR MAJOR STOCKHOLDERS HAS THE EFFECT OF
ALLOWING THEM TO NOMINATE SIX OF OUR TWELVE DIRECTORS, WHICH LIMITS THE ABILITY
OF NEW INVESTORS TO INFLUENCE CONTROL OF AETHER.

NexGen Technologies, L.L.C., Telcom-ATI Investors, L.L.C. and Reuters
MarketClip Holdings Sarl, a subsidiary of Reuters Group Plc. -- who together
hold 24.3% of the shares of our common stock -- entered into a stockholder
agreement that governs voting for our directors. The agreement provides that
each party will vote all of its shares for one director nominated by NexGen, two
directors nominated by Telcom-ATI Investors, two directors nominated jointly by
NexGen and Telcom-ATI Investors and one director nominated by Reuters. As a
result, six directors of our board are nominated by these major stockholders. As
we currently have authorized only 12 directors, the voting rights of our
stockholders other than these major stockholders effectively will be
meaningfully exercised only in connection with the election of six of our
directors. In addition to its effect on the voting rights of our new investors,
the stockholder agreement could have the effect of delaying or preventing a
change in control.

4
6

WE HAVE ANTI-TAKEOVER DEFENSES THAT COULD DELAY OR PREVENT AN ACQUISITION OF
AETHER AND COULD ADVERSELY AFFECT THE PRICE OF OUR COMMON STOCK.

Provisions of our certificate of incorporation and bylaws and provisions of
Delaware law could delay, defer or prevent an acquisition or change of control
of Aether or otherwise adversely affect the price of our common stock. For
example, our bylaws limit the ability of stockholders to call a special meeting.
Moreover, our certificate of incorporation permits our board to issue shares of
preferred stock without stockholder approval, which means that the board could
issue shares with special voting rights or other provisions that could deter a
takeover. In addition to delaying or preventing an acquisition, the issuance of
a substantial number of preferred shares could adversely affect the price of our
common stock.

FORWARD-LOOKING STATEMENTS

This prospectus includes forward-looking statements within the meaning of
Section 27A of the Securities Act and Section 21E of the Securities Exchange
Act. We have based these forward-looking statements on our current expectations
and projections about future events. In some cases, you can identify
forward-looking statements by terminology such as "may," "will," "should,"
"could," "pending," "potential," "continue," "expects," "anticipates,"
"intends," "plans," "believes," "predicts," "estimates" and similar expressions,
although not all forward-looking statements are identified by these words. These
forward-looking statements are subject to a number of risks, uncertainties and
assumptions about Aether and our industry, including those we describe in the
"Risk Factors" section of this prospectus. In light of these risks,
uncertainties and assumptions, the forward-looking events discussed in this
prospectus might not occur. We undertake no obligation to publicly update or
revise any forward-looking statements, whether as a result of new information,
future events or otherwise.

USE OF PROCEEDS

This prospectus relates to shares of our common stock being offered and
sold for the accounts of the selling stockholders named in this prospectus. We
will not receive any proceeds from the shares sold pursuant to this prospectus.

5
7

SELLING STOCKHOLDERS

The following table sets forth certain information with respect to
beneficial ownership of our common stock as of April 30, 2001, as adjusted to
reflect the sale of 3,023,560 shares of common stock pursuant to this
prospectus, as to each stockholder selling shares of our common stock pursuant
to this prospectus.

Except as indicated in the footnotes to this table and under applicable
community property laws, to our knowledge, the persons named in the table have
sole voting and investment power with respect to all shares of common stock. For
the purposes of calculating percent ownership as of April 30, 2001, 40,529,594
shares were issued and outstanding.

The persons selling shares pursuant to this prospectus may include
pledgees, donees, transferees or other successors in interest of the persons
identified below as selling stockholders.

OWNERSHIP OF SHARES OF OWNERSHIP OF
SHARES BEFORE THE COMMON SHARES AFTER THE
OFFERING STOCK OFFERING(1)
----------------- COVERED BY THIS -----------------
SELLING STOCKHOLDERS NUMBER PERCENT PROSPECTUS NUMBER PERCENT
-------------------- ------- ------- --------------- ------- -------

Columbia Riverbed Partners, LLC................ 559,279 1.4% 559,279 0 *
Columbia Capital Equity Partners II (QP),
L.P. ........................................ 514,309 1.3% 514,309 0 *
George Abraham................................. 331 * 331 0 *
Albert Abramson................................ 5,296 * 5,296 0 *
Linda Beers.................................... 2,648 * 2,648 0 *
Berman Enterprises, L.P........................ 9,003 * 9,003 0 *
Gary Berman.................................... 5,296 * 5,296 0 *
Dennis Berman.................................. 5,296 * 5,296 0 *
Delores K. Berman Revocable Trust.............. 3,177 * 3,177 0 *
Helene E. Berman Revocable Trust............... 3,177 * 3,177 0 *
Eric Billings.................................. 2,648 * 2,648 0 *
James H.R. Brady............................... 662 * 662 0 *
Graeme Bush.................................... 3,177 * 3,177 0 *
Lawrence Cirka................................. 5,296 * 5,296 0 *
Neil Cohen..................................... 5,296 * 5,296 0 *
Colony Partners................................ 5,296 * 5,296 0 *
CNF Investment, LLC(2)......................... 42,365 * 42,365 0 *
Clark Enterprises, Inc....................... 29,655 * 29,655 0 *
Robert Flanagan.............................. 4,236 * 4,236 0 *
Lawrence Nossdorf............................ 4,237 * 4,237 0 *
A. James Clark............................... 4,237 * 4,237 0 *
Cyclops Family Partnership..................... 2,648 * 2,648 0 *
Thomas C. Dexter, Jr. ......................... 530 * 530 0 *
Andrew Dixon................................... 1,059 * 1,059 0 *
Andrew & Jean Dixon............................ 1,059 * 1,059 0 *
Robert Duvall.................................. 2,648 * 2,648 0 *
Michael Epstein................................ 5,296 * 5,296 0 *
Samantha Epstein IRR Trust..................... 1,059 * 1,059 0 *
Marshall Ezralow IRA........................... 5,296 * 5,296 0 *
Investment Management Inc...................... 10,088 * 10,088 0 *
FBR Venture Capital Managers, Inc.............. 56,590 * 56,590 0 *
Robert Feinstein............................... 6,355 * 6,355 0 *
Kenneth O. Frederick........................... 2,648 * 2,648 0 *
Emanuel Friedman............................... 6,355 * 6,355 0 *
Grass Roots Investment Fund.................... 2,648 * 2,648 0 *
Robert Hartheimer.............................. 1,059 * 1,059 0 *
David Hilal.................................... 662 * 662 0 *
Richard Horstmann.............................. 1,059 * 1,059 0 *
Karfunkel Family Foundation.................... 10,591 * 10,591 0 *
Kettle Family, L.P............................. 10,591 * 10,591 0 *

6
8

James Kleeblatt................................ 530 * 530 0 *
Lerner Family Foundation, Inc.................. 10,591 * 10,591 0 *
Kenneth Logue.................................. 1,589 * 1,589 0 *
Walter & Delaney Lundberg...................... 1,059 * 1,059 0 *
John F. Mangan, Jr. ........................... 1,589 * 1,589 0 *
Mario M. Morino Trust.......................... 10,591 * 10,591 0 *
Robert J. Martin............................... 662 * 662 0 *
Milloy Family Technology Partnership, L.P...... 4,236 * 4,236 0 *
Dominic Ng..................................... 1,059 * 1,059 0 *
B.F. Saul Company Employees' Profit Sharing
Retirement Trust............................. 21,183 * 21,183 0 *
Raymond Rice................................... 1,589 * 1,589 0 *
Suzanne Richardson............................. 3,707 * 3,707 0 *
RJA Property Company, LLC...................... 702 * 702 0 *
RNR, LLC....................................... 29,126 * 29,126 0 *
Riyad & Madeleine Said......................... 794 * 794 0 *
Thomas Scott................................... 5,296 * 5,296 0 *
William & Marcia Scott......................... 530 * 530 0 *
Alan Shusterman................................ 2,118 * 2,118 0 *
Cal Simmons.................................... 10,591 * 10,591 0 *
Gordon V. and Helen C. Smith Foundation........ 10,591 * 10,591 0 *
South Ferry #2, L.P............................ 42,365 * 42,365 0 *
Charles Vance.................................. 21,183 * 21,183 0 *
Edward Wheeler................................. 794 * 794 0 *
Wolfson Equities L.P........................... 10,591 * 10,591 0 *
Gregory M. Wong................................ 993 * 993 0 *
WR&F Associates IV Pool 2(3)................... 6,355 * 6,355 0 *
Bruce Joseph................................. 529 * 529 0 *
John Wyss.................................... 529 * 529 0 *
James Wallace................................ 1,062 * 1,062 0 *
Richard Bodorff.............................. 529 * 529 0 *
Richard McConnell............................ 529 * 529 0 *
William Baker................................ 529 * 529 0 *
Bert Rein.................................... 1,061 * 1,061 0 *
John Bartlett................................ 529 * 529 0 *
Fred Fielding................................ 529 * 529 0 *
Walter Andrew................................ 529 * 529 0 *
Alan L. & Irene V. Wurtzel Revocable Trust..... 2,648 * 2,648 0 *
Peter T. Young................................. 1,059 * 1,059 0 *
Gene Riechers.................................. 40,893 * 40,893 0 *
Hooks Johnston................................. 26,203 * 26,203 0 *
Scott Frederick................................ 6,551 * 6,551 0 *
Harry Weller................................... 6,551 * 6,551 0 *
Alvin L. Ring.................................. 223,647 * 139,991 41,828 *
Spencer Kravitz(4)............................. 458,060 1.1% 286,720 85,670 *
Jay Moskowitz(4)............................... 458,735 1.1% 287,143 85,796 *
Bruce Laskin(5)................................ 87,153 * 54,553 16,300 *
Michael Druckman............................... 13,512 * 8,458 2,527 *
Alan Kuritsky.................................. 2,026 * 1,268 379 *
America Online................................. 61,235 * 61,235 0 *
Monsoon Ventures LLC........................... 130,636 * 130,636 0 *
Monsoon Management Inc. ....................... 46,308 * 46,308 0 *
Chemical Investments, Inc. .................... 8,711 * 8,711 0 *

7
9

Sandra Laskin, as Custodian for Michael Jacob
Laskin....................................... 300 * 300 0 *
Sandra Laskin, as Custodian for David Laskin... 300 * 300 0 *
Rhonda Greenstein Kravitz, as Custodian for
Evan Kravitz................................. 599 * 599 0 *
Rhonda Greenstein Kravitz, as Custodian for
Ariel Kravitz................................ 599 * 599 0 *
Leonard Fremont................................ 60 * 60 0 *
Debbie Moskowitz, as Custodian for Erik
Moskowitz.................................... 300 * 300 0 *
Debbie Moskowitz, as Custodian for Leah
Danielle..................................... 300 * 300 0 *
Manufacturers Life............................. 36,118 * 32,238 3,880 *
JAFCO Co., Ltd................................. 3,169 * 2,830 339 *
JAFCO G-6(A) Investment Enterprise
Partnership.................................. 2,739 * 2,445 294 *
JAFCO G-6(B) Investment Enterprise
Partnership.................................. 2,739 * 2,445 294 *
JAFCO JS-3 Investment Enterprise Partnership... 1,826 * 1,630 196
JAFCO R-3 Investment Enterprise Partnership.... 3,044 * 2,717 327 *
U.S. Information Technology No. 2 Investment
Enterprise Partnership....................... 54,082 * 48,272 5,810 *
Atlas Venture Fund II, L.P. ................... 123,280 * 110,035 13,345 *
Sigma Partners III, L.P. ...................... 91,378 * 81,562 9,816 *
Sigma Associates III, L.P. .................... 13,764 * 12,287 1,477 *
Sigma Investors III, L.P. ..................... 1,683 * 1,504 179 *
Commonwealth Capital Ventures.................. 67,755 * 60,477 7,278 *
OneLiberty Fund III, L.P. ..................... 24,488 * 21,858 2,630 *
Gilde International B.V. ...................... 202 * 181 21 *
Adams Harkness & Hill Partner Fund............. 7,261 * 6,482 779 *
Robert Davoli and Eileen McDonagh.............. 4,908 * 4,382 526 *
Robert Davoli.................................. 924 * 825 99 *
John R. Mandile................................ 965 * 862 103 *
Gardner Hendrie................................ 8,217 * 7,336 881 *
Robert Badavas................................. 9,625 * 8,592 1,033 *
Thomas R. Holler............................... 1,282 * 1,145 137 *
William J. Reich............................... 482 * 431 51 *
William C. Poellmitz........................... 482 * 431 51 *

---------------
* Less than 1%.

(1) Assuming all of the shares covered by this prospectus are sold.

(2) CNF Investments LLC currently owns all of the 42,365 shares of common stock
shown as being held by it. From time to time, CNF Investments LLC may
distribute a portion or all of its shares to the four selling stockholders
identified below CNF Investments LLC, and the number of shares shown
opposite each such name is the maximum number of shares that might be
distributed to such person and the maximum number of shares that may be
offered by them under this prospectus.

(3) WR&F Associates IV Pool 2 currently owns all of the 6,355 shares of common
stock shown as being held by it. From time to time, WR&F Associates IV Pool
2 may distribute a portion or all of its shares to the 10 selling
stockholders identified below. WR&F Associates IV Pool 2, and the number of
shares shown opposite each such name is the maximum number of shares that
might be distributed to such person and the maximum number of shares that
may be offered by them under this prospectus.

8
10

(5) Spencer Kravitz and Jay Moskowitz have each agreed not to sell or otherwise
transfer the shares registered under this registration statement, until the
dates and in the amounts indicated below:

JULY 1, OCTOBER 1, JAN. 1, APRIL 1, JULY 1, OCTOBER 1,
2001 2001 2002 2002 2002 2002
------- ---------- ------- -------- ------- ----------

Kravitz...................... 62,991 62,991 62,992 62,991 62,991 62,992
Moskowitz.................... 63,084 63,084 63,085 63,084 63,084 63,085

(6)Bruce Laskin has agreed not to sell or otherwise transfer shares registered
under this registration statement, except that 17,977 shares will be eligible
for sale on July 1, 2001; 17,978 shares will be eligible for sale on October
1, 2001; 17,978 shares will be eligible for sale on January 1, 2002; and
17,978 shares will be eligible for sale on April 1, 2002.

9
11

PLAN OF DISTRIBUTION

We have been advised that the selling stockholders (and their pledgees,
donees, transferees and other successors in interest) may offer shares of common
stock from time to time depending on market conditions and other factors, in one
or more transactions on the Nasdaq National Market, or any other national
securities exchanges or over-the-counter markets on which the shares may be
traded, or in negotiated transactions, at market prices prevailing at the time
of sale, at prices related to those market prices, at negotiated prices or at
fixed prices.

Sales of shares of common stock by the selling stockholders may involve (i)
block transactions in which the broker or dealer so engaged will attempt to sell
the shares as agent but may position and resell a portion of the block as
principal to facilitate the transaction, (ii) purchases by a broker-dealer as
principal and resale by such broker-dealer for its own account pursuant to this
prospectus, (iii) ordinary brokerage transactions and transactions in which a
broker solicits purchasers or (iv) privately negotiated transactions. To the
extent required, this prospectus may be amended and supplemented from time to
time to describe a specific plan of distribution. In connection with the
distribution of the shares of common stock or otherwise, the selling
stockholders may enter into hedging transactions with broker-dealers. In
connection with such transactions, broker-dealers may engage in short sales of
the common stock in the course of hedging the position they assume with the
selling stockholders. The selling stockholders may also sell the common stock
short and redeliver the shares to close out such short positions.

The selling stockholders may also enter into option transactions (including
call or put option transactions) or other transactions with broker-dealers which
require delivery to such broker-dealer of shares offered hereby, which shares
such broker-dealer may resell pursuant to this prospectus (as supplemented or
amended to reflect such transaction, if necessary). The selling stockholders may
also pledge shares to a broker-dealer and, upon a default, such broker-dealer
may effect sales of the pledged shares pursuant to this prospectus (as
supplemented or amended to reflect such transaction, if necessary). The selling
stockholders may also sell the common stock through one or more underwriters on
a firm commitment or best-efforts basis (with a supplement or amendment to this
prospectus, if necessary). In addition, any shares that qualify for sale
pursuant to Rule 144 may be sold under Rule 144 rather than pursuant to this
prospectus.

Brokers and dealers may receive compensation in the form of concessions or
commissions from the selling stockholders and/or purchasers of shares for whom
they may act as agent and/or to whom they may sell as principal (which
compensation may be in excess of customary commissions). The selling
stockholders and any broker or dealer that participates in the distribution of
shares may be deemed to be underwriters and any commissions received by them and
any profit on the resale of shares positioned by a broker or dealer may be
deemed to be underwriting discounts and commissions under the Securities Act. We
have agreed to indemnify the selling stockholders, the officers, directors,
partners, agents and employees of the selling stockholders, any underwriter (as
defined in the Securities Act) for such selling stockholder, and each person, if
any, who controls such selling stockholder or underwriter within the meaning of
the Securities Act or the Exchange Act against certain liabilities, including
liabilities arising under the Securities Act or the Exchange Act. The selling
stockholders may agree to indemnify any agent or broker-dealer that participates
in transactions involving sales of the shares of common stock against certain
liabilities, including liabilities arising under the Securities Act.

We have advised the selling stockholders that Regulation M under the
Exchange Act may apply to sales of shares and to the activities of the selling
stockholders or broker-dealers in connection therewith. We will bear all costs,
expenses and fees in connection with the registration of the shares of common
stock covered by this prospectus. The selling stockholders will bear any
brokerage commissions and similar selling expenses, if any, attributable to the
sale of the shares.

The selling stockholders may also sell shares under Rule 144 under the
Securities Act, if available, rather than under this prospectus.

10
12

LEGAL MATTERS

The validity of the common stock offered hereby will be passed upon for
Aether by Wilmer, Cutler & Pickering, Washington, D.C.

EXPERTS

The consolidated financial statements and schedule of Aether Systems, Inc.
as of December 31, 1999 and 2000, and for each of the years in the three-year
period ended December 31, 2000, have been incorporated by reference herein and
in the registration statement in reliance upon the reports of KPMG LLP,
independent certified public accountants, which as to the year 2000, is based in
part on the report of Ernst & Young, independent auditors. These reports,
incorporated by reference herein, are given on the authority of said firms as
experts in accounting and auditing.

The financial statements of LocusOne Communications, Inc. as of December
31, 1998 and 1999, and for each of the years then ended have been incorporated
by reference in this prospectus and elsewhere in the registration statement in
reliance upon the report of KPMG LLP, independent certified public accountants,
incorporated by reference herein, and upon the authority of said firm as experts
in accounting and auditing.

The financial statements of Riverbed Technologies, Inc. as of December 31,
1998 and 1999, and for the period from October 21, 1998 (date of inception) to
December 31, 1998 and for the year ended December 31, 1999, have been
incorporated by reference in this prospectus and elsewhere in the registration
statement in reliance upon the report of KPMG LLP, independent certified public
accountants, incorporated by reference herein, and upon the authority of said
firm as experts in accounting and auditing.

The financial statements of Mobeo, Inc. as of December 31, 1997 and 1998
and for each of the three years in the period ended December 31, 1998 have been
incorporated by reference in this prospectus and elsewhere in the registration
statement in reliance on the report of PricewaterhouseCoopers LLP, independent
accountants, given on the authority of said firm as experts in auditing and
accounting.

WHERE YOU CAN FIND MORE INFORMATION

We are subject to the informational requirements of the Securities Exchange
Act and we file reports, proxy and information statements and other information
with the SEC. You may read and copy all or any portion of the reports, proxy and
information statements or other information we file at the SEC's principal
office in Washington, D.C., and copies of all or any part thereof may be
obtained from the Public Reference Section of the SEC, 450 Fifth Street, N.W.,
Washington, D.C. 20549, and at the SEC's regional offices located at Citicorp
Center, 500 West Madison Street, Suite 1400, Chicago, Illinois 60661 and at 7
World Trade Center, 13th Floor, New York, New York 10048 after payment of fees
prescribed by the SEC. Please call the SEC at 1-800-SEC-0330 for further
information on operation of the public reference rooms. The SEC also maintains a
Web site which provides online access to reports, proxy and information
statements and other information regarding registrants that file electronically
with the SEC at the address http://www.sec.gov.

We have filed with the SEC a Registration Statement on Form S-3 under the
Securities Act with respect to the common stock to be sold in this offering.
This prospectus does not contain all of the information set forth in the
Registration Statement and the exhibits to the Registration Statement. For
further information with respect to Aether and our common stock offered hereby,
reference is made to the Registration Statement and the exhibits filed as a part
of the Registration Statement. Statements contained in this prospectus
concerning the contents of any contract or any other document are not
necessarily complete; reference is made in each instance to the copy of such
contract or any other document filed as an exhibit to the Registration
Statement. Each such statement is qualified in all respects by such reference to
such exhibit. The Registration Statement, including exhibits thereto, may be
inspected without charge at the locations described above, or obtained upon
payment of fees prescribed by the SEC.

11
13

The Securities and Exchange Commission also allows Aether to "incorporate
by reference" information into this prospectus. This means that Aether can
disclose important information to you by referring you to another document filed
separately with the Securities and Exchange Commission. The information
incorporated by reference is considered to be part of this prospectus, except
for any information that is superseded by information that is included directly
in this document, or any future filings with the Securities and Exchange
Commission made under Sections 13(a), 13(c), 14 or 15(d) of the Securities
Exchange Act of 1934.

This prospectus incorporates by reference the documents listed below:

- Aether's Annual Report on Form 10-K, as amended, for the fiscal year
ended December 31, 2000.

- Aether's Current Report on Form 8-K dated April 16, 2001, including any
amendments.

- The financial statements of LocusOne Communications and Riverbed
Technologies included in Aether's Registration Statement on Form S-1
(File No. 333-44566), as amended.

- The Description of Capital Stock contained in Aether's Registration
Statement on Form S-1 (Registration No. 333-45656) dated September 27,
2000, including any amendments or reports filed for the purpose of
updating such description.

- In addition, all documents subsequently filed by Aether pursuant to
Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the
termination of the offering shall be deemed to be incorporated by
reference herein from their respective dates of filing.

You may request a copy of any filings incorporated by reference in this
prospectus from Aether by contacting:

Kevin Connelly
VP Finance and Accounting
Aether Systems, Inc.
11460 Cronridge Drive
Owings Mills, Maryland 21117
Telephone: (410) 654-6400

You should rely only on the information incorporated by reference or
provided in this prospectus. Aether has not authorized anyone else to provide
you with different or additional information. You should not assume that the
information in this prospectus is accurate as of any date other than the date
set forth on the front cover.

12
14

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

3,023,560 SHARES

[AETHER LOGO]

COMMON STOCK

----------------------
PROSPECTUS
----------------------

MAY 1, 2001

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
15

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

The expenses to be paid by Aether Systems, Inc. ("Aether" or "Aether
Systems") in connection with the distribution of the securities being registered
are as follows:

TOTAL
AMOUNT(1)
---------

Securities and Exchange Commission Registration Fee......... $19,276
Accounting Fees and Expenses................................ 10,000
Legal Fees and Expenses..................................... 40,000
Printing and Engraving Expenses............................. 10,000
Miscellaneous Fees and Expenses............................. 10,724
-------
Total............................................. $90,000
=======

---------------
(1) All amounts are estimates except the SEC filing fee.

ITEM 15. INDEMNIFICATION OF DIRECTORS AND OFFICERS

Under Section 145 of the General Corporate law of the State of Delaware,
Aether Systems has broad powers to indemnify its directors and officers against
liabilities they may incur in such capacities, including liabilities under the
Securities Act of 1933, as amended (the "Securities Act"). Aether Systems'
bylaws (Exhibit 3.2 hereto) also provide for mandatory indemnification of its
directors and executive officers, and permissive indemnification of its
employees and agents, to the fullest extent permissible under Delaware law.

Aether's certificate of incorporation (Exhibits 3.1 and 3.3 hereto)
provides that the liability of its directors for monetary damages shall be
eliminated to the fullest extent permissible under Delaware law. Pursuant to
Delaware law, this includes elimination of liability for monetary damages for
breach of the directors' fiduciary duty of care to Aether and its stockholders.
These provisions do not eliminate the directors' duty of care and, in
appropriate circumstances, equitable remedies such as injunctive or other forms
of non-monetary relief will remain available under Delaware law. In addition,
each director will continue to be subject to liability for breach of the
director's duty of loyalty to Aether, for acts or omissions not in good faith or
involving intentional misconduct, for knowing violations of law, for any
transaction from which the director derived an improper personal benefit, and
for payment of dividends or approval of stock repurchases or redemptions that
are unlawful under Delaware law. The provision also does not affect a director's
responsibilities under any other laws, such as the federal securities laws or
state or federal environmental laws.

Aether has entered into agreements with its directors and certain of its
executive officers that require Aether to indemnify such persons against
expenses, judgments, fines, settlements and other amounts actually and
reasonably incurred (including expenses of a derivative action) in connection
with any proceeding, whether actual or threatened, to which any such person may
be made a party by reason of the fact that such person is or was a director or
officer of Aether or any of its affiliated enterprises, provided such person
acted in good father and in a manner such person reasonably believed to be in or
not opposed to the best interests of Aether and, with respect to any criminal
proceeding, had no reasonable cause to believe his or her conduct was unlawful.
The indemnification agreements also set forth certain procedures that will apply
in the event of a claim for indemnification thereunder.

Aether has a policy of directors' and officers' liability insurance that
insures Aether's directors and officers against the cost of defense, settlement
or payment of a judgment under certain circumstances.

II-1
16

The Underwriting Agreement filed as Exhibit 1.1 to this Registration
Statement provides for indemnification by the underwriters of Aether and its
officers and directors for certain liabilities arising under the Securities Act
or otherwise.

ITEM 16. EXHIBITS

The exhibit index is incorporated by reference.

ITEM 17. UNDERTAKINGS

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this Registration Statement:

(i) To include any prospectus required by Section 10(a)(3) of the
Securities Act of 1933, as amended (the "Securities Act");

(ii) To reflect in the prospectus any facts or events arising after
the effective date of this Registration Statement (or the most recent
post-effective amendment thereof) which, individually or in the
aggregate, represent a fundamental change in the information set forth
in this Registration Statement. Notwithstanding the foregoing, any
increase or decrease in the volume of securities offered (if the total
dollar value of securities offered would not exceed that which was
registered) and any deviation from the low or high end of the estimated
maximum offering range may be reflected in the form of prospectus filed
with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than 20 percent change in
the maximum aggregate offering price set forth in the "Calculation of
Registration Fee" table in the effective Registration Statement; and

(iii) To include any material information with respect to the plan
of distribution not previously disclosed in this Registration Statement
or any material change to such information in this Registration
Statement;

provided, however, that paragraphs (1)(i) and (1)(ii) do not apply if
the information required to be included in a post-effective amendment by
those paragraphs is contained in periodic reports filed with or
furnished to the Commission by the Company pursuant to Section 13 or
Section 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), that are incorporated by reference in this Registration
Statement.

(2) That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a
new registration statement relating to the securities offered therein, and
the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the
termination of the offering.

The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the Company's
annual report pursuant to section 13(a) or section 15(d) of the Exchange Act
(and, where applicable, each filing of an employee benefit plan's annual report
pursuant to section 15(d) of the Exchange Act) that is incorporated by reference
in the Registration Statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act
may be permitted to directors, officers and controlling persons of the
registrant pursuant to the foregoing provisions, or otherwise, the registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In
II-2
17

the event that a claim for indemnification against such liabilities (other than
the payment by the registrant of expenses incurred or paid by a director,
officer or controlling person of the registrant in the successful defense of any
action, suit or proceeding) is asserted by such director, officer or controlling
person in connection with the securities being registered, the registrant will,
unless in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the Act and
will be governed by the final adjudication of such issue.

II-3
18

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant
has duly caused this amendment to registration statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of Owings
Mills, State of Maryland on the 30th day of April, 2001.

Aether Systems, Inc.

By: /s/ DAVID C. REYMANN
----------------------------------
David C. Reymann
Chief Financial Officer

Pursuant to the requirements of the Securities Act of 1933, this Amendment
No. 1 to Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.

SIGNATURE TITLE DATE
--------- ----- ----

* Chairman and Chief Executive Officer April 30, 2001
------------------------------------------------
David S. Oros

* Chief Financial Officer (Principal April 30, 2001
------------------------------------------------ Financial and Accounting Officer)
David C. Reymann

* Director April 30, 2001
------------------------------------------------
J. Carter Beese, Jr.

* Director April 30, 2001
------------------------------------------------
Frank A. Bonsal, Jr.

* Director April 30, 2001
------------------------------------------------
Mark D. Ein

* Director April 30, 2001
------------------------------------------------
Dr. Rajendra Singh

* Director April 30, 2001
------------------------------------------------
George P. Stamas

* Director April 30, 2001
------------------------------------------------
Thomas E. Wheeler

* /s/ DAVID C. REYMANN
------------------------------------------------
David C. Reymann
Attorney-in-fact

II-4
19

EXHIBIT INDEX

EXHIBIT
NUMBER DOCUMENT AND DESCRIPTION
------- ------------------------

*2.1 -- Agreement of Merger, dated as of October 18, 1999,
between Aether Systems LLC, and Aether Systems, Inc.
*2.2 -- Stock Purchase Agreement by and among Aether Technologies
International, L.L.C., Mobeo, Inc. and Peter Kibler,
Winston Barrett and Edward Spear dated as of August 19,
1999.
**2.3 -- Stock Purchase Agreement by and among Aether Systems,
Inc., LocusOne Communications, Inc. and the stockholders
named therein dated as of January 25, 2000
+2.4 -- Agreement and Plan of Merger dated as of February 9, 2000
by and among Aether Systems, Inc., RT Acquisition, Inc.
and Riverbed Technologies, Inc.
++2.5 -- LLC Interest Purchase Agreement made effective as of
April 18, 2000 by and among Aether Systems, Inc., Net
Search LLC and the members of Net Search, LLC and
Augustine N. Esposito
++2.6 -- Share Purchase Agreement relating to IFX Group Limited
***2.7 -- Agreement and Plan of Merger by and among Aether Systems,
Inc. and Cerulean Technology, Inc.
*4.1 -- Specimen Certificate for Aether Systems Common Stock
+4.2 -- Form of Indenture for Convertible Debt
5.1 -- Opinion of Wilmer, Cutler & Pickering as to the legality
of the shares of Common Stock being registered
++++21.1 -- Subsidiaries of Aether Systems
23.1 -- Consent of KPMG LLP for Aether Systems, Inc.
23.2 -- Consent of Wilmer, Cutler & Pickering, included in
Exhibit 5.1
23.3 -- Consent of KPMG LLP for LocusOne Communications, Inc.
23.4 -- Consent of KPMG LLP for Riverbed Technologies, Inc.
23.5 -- Consent of Ernst & Young
23.6 -- Consent of PricewaterhouseCoopers

---------------

* Incorporated by reference to the Registration Statement
(File No. 333-85697) on Form S-1 filed with the Commission
on October 20, 1999, as amended.
** Incorporated by reference to the Form 8-K filed with the
Commission on February 15, 2000.
*** Incorporated by reference to the Registration Statement
(File No. 333-44566) on Form S-1 filed with the Commission
on September 7, 2000, as amended.
+ Incorporated by reference to the Registration Statement
(File No. 333-30852) or Form S-1 filed with the Commission
on February 22, 2000, as amended.
++ Incorporated by reference to the Form 10-Q filed with the
Commission on August 14, 2000.
++++ Previously filed.