As filed with the Securities and Exchange Commission on November 19, 1999

                                            Registration No. 333_______________

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


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                    Form S-8
                             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 of                            (I.R.S. employer
 incorporation or organization)                         identification number)

                              11460 Cronridge Drive
                          Owings Mills, Maryland 21117
                    (Address of Principal Executive Offices)

                                 (410) 654-6400
              (Registrant's telephone number, including area code)

                              Aether Systems, Inc.
                           1999 Equity Incentive Plan
                            (Full title of the plan)

                                  David S. Oros
                             Chairman of the Board,
                       Chief Executive Officer & President

                              Aether Systems, Inc.
                              11460 Cronridge Drive
                          Owings Mills, Maryland 21117
                                 (410) 654-6400
          (Name and address, including zip code, and telephone number,
                   including area code, of agent for service)

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

                                 With a copy to:

                             R. Scott Kilgore, Esq.
                           Wilmer, Cutler & Pickering
                               2445 M Street, N.W.
                             Washington, D.C. 20037

                           ---------------------------
<PAGE>
 <TABLE>
<CAPTION>


                                               CALCULATION OF REGISTRATION FEE



<S>                       <C>                         <C>                <C>              <C>               <C>
                                                                          Proposed           Proposed
                               Title of                                    Maximum            Maximum
                              Securities                  Amount          Offering           Aggregate          Amount of
                                to be                     to be            Price             Offering        Registration
         Name of Plan         Registered                Registered       Per Share (1)        Price (1)           Fee (1)
------------------------------------------------------------------------------------------------------------------------------------
1999 Equity Incentive     Common Stock, par $0.01       5,400,000          $31.98          $172,690,096         $48,008
Plan (the "1999 Plan")
------------------------------------------------------------------------------------------------------------------------------------


<FN>


(1) In accordance with Rule 457(h) and Rule 457(c) the aggregate offering price and the amount of the registration fee are
    computed on the basis of (a) for 2,481,091 shares not yet subject to options, $66.69, the average of the high and low
    prices reported in the Nasdaq Stock Market on November 12, 1999, and (b) for granted options for 2,918,959 shares, the
    actual exercise prices specified in those granted options (which range from $0.40 to $8.00.) Also registered hereunder
    are such additional number of shares of Common Stock, presently indeterminable, as may be necessary to satisfy the
    antidilution provisions of the Plan to which this Registration Statement relates.


</FN>
</TABLE>

                                      - 2 -

<PAGE>

                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

                  Note: The document(s)  containing the information  required by
Item 1 of Form S-8 and the statement of availability  of registrant  information
and any other  information  required by Item 2 of Form S-8 will be sent or given
to  participants  as specified by Rule 428 under the  Securities Act of 1933, as
amended (the "Securities Act"). In accordance with Rule 428 and the requirements
of Part I of Form S-8, such documents are not being filed with the SEC either as
part of this Registration Statement or as prospectuses or prospectus supplements
pursuant  to Rule 424  under the  Securities  Act.  Aether  Systems,  Inc.  (the
"Registrant"  or the  "Company")  shall  maintain  a file of such  documents  in
accordance with the provisions of Rule 428. Upon request,  the Registrant  shall
furnish the SEC or its staff a copy or copies of all of the  documents  included
in such file.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

                  The Company  hereby  incorporates  by reference  the documents
listed in (a) through (c) below. In addition,  all documents  subsequently filed
by the Company pursuant to Section 13(a),  13(c), 14 and 15(d) of the Securities
Exchange  Act of 1934,  as amended  (the  "Exchange  Act") (prior to filing of a
Post-Effective  Amendment which indicates that all securities  offered have been
sold or which  deregisters all securities then remaining unsold) shall be deemed
to be incorporated by reference in this Registration  Statement and to be a part
hereof from the date of filing of such documents.

         (a) Prospectus on Form 424B4 filed by the Company on October 21, 1999.

         (b) The Company's Registration Statement on Form S-1 (SEC No.333-85697
             filed by the Company on August 20, 1999 and all amendments
             thereafter.

         (c) The   description   of  the  Company's   Common  Stock  which  is
             incorporated by reference from the Prospectus on Form 424B4 filed
             by the Company on October 21, 1999,  including  any  amendment or
             report filed for the purpose of updating such description.


Item 4. Description of Securities

           Not Applicable


Item 5.   Interests of Named Experts and Counsel

                  The validity of the shares of Company Common Stock that may be
issued under  options  granted  under the 1999 Plan is being passed upon for the
Company by Wilmer,  Cutler & Pickering.  George P. Stamas, a member of the Board
of Directors, is a partner in Wilmer, Cutler & Pickering. As of the date of this
Registration Statement,  Mr. Stamas had received stock options to purchase
23,850 shares of Common Stock and he holds a non-voting interest in  Telcom-ATI
Investors.

                                      - 3 -

<PAGE>


Item 6.   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  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   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.

                  Prior to the  effective  date of the  Registration  Statement,
Aether will have entered into  agreements  with its directors and certain of its
executive  officers that require Aether to indemnify  such persons  against II-1
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
maybe  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 intends to obtain in conjunction with the effectiveness
of the  Registration  Statement 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.

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


Item 7.   Exemption from Registration Claimed

          Not Applicable.

                                      - 4 -
<PAGE>



Item 8.   Exhibits

The Exhibit Index attached to this Registration Statement is incorporated herein
by reference.

Item 9.   Undertakings

(a)       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;

                           (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;

                           (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 (a)(1)(i) and (a)(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 by the registrant pursuant to section
                    13  or  section   15(d)  of  the   Exchange   Act  that  are
                    incorporated by reference in the 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.

(b)       The undersigned  Registrant  hereby  undertakes  that, for purposes of
          determining any liability under the Securities Act, each filing of the
          Registrant's  annual report pursuant to section 13(a) or section 15(d)
          of the  Exchange  Act  (and,  where  applicable,  each  filing  of any
          employee benefit plan's annual report pursuant to section 15(d) of the
          Exchange Act) that is incorporated  by reference in this  Registration
          Statement shall be deemed to be a new registration statement reflating
          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.

                                      - 5 -

<PAGE>

(c)       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
          SEC such  indemnification is against public policy as expressed in the
          Securities Act and is, therefore,  unenforceable.  In 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
          of whether  such  indemnification  by it is against  public  policy as
          expressed  in the  Securities  Act and will be  governed  by the final
          adjudication of such issue.

            [The remainder of this page is intentionally left blank.]













                                      - 6 -

<PAGE>

                                   SIGNATURES

                  Pursuant to the  requirements  of the  Securities Act of 1933,
the Company  certifies that it has  reasonable  grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in Owings Mill, Maryland on the 18th day of November, 1999.

                                                AETHER SYSTEMS, INC.

                                                By:  /s/ David S. Oros
                                                -------------------------------
                                                David S. Oros
                                                Chief Executive Office


                                POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS,  that each person whose signature  appears below
under the heading  "Signature"  constitutes and appoints David S. Oros and David
C.  Reymann as his or her true and lawful  attorney-in-fact  each acting  alone,
with full power of substitution and resubstitution, for him or her and in his or
her  name,  place  and  stead,  in any and  all  capacities  to sign  any or all
amendments (including post-effective amendments) to this Registration Statement,
and to file  the  same,  with all  exhibits  thereto,  and  other  documents  in
connection therewith, with the Securities and Exchange Commission, granting unto
said  attorney-in-fact full power and authority to do and perform each and every
act and thing  requisite and necessary to be done in and about the premises,  as
fully for all  intents  and  purposes  as he or she might or could do in person,
hereby  ratifying and confirming all that said  attorney-in-fact,  or his or her
substitute, acting alone, may lawfully do or cause to be done by virtue hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the dates indicated.

    Signature                            Title                      Date


                                Chairman of the Board,
/s/ David S. Oros               Chief Executive Officer
------------------------        and President                 November 18, 1999
David S. Oros


/s/ David C. Reymann
------------------------        Chief Financial Officer       November 18, 1999
David C. Reymann


/s/ J. Carter Beese, Jr.
------------------------        Director                      November 18, 1999
J. Carter Beese, Jr.


/s/ Frank A. Bonsal, Jr.
------------------------        Director                      November 18, 1999
Frank A. Bonsal, Jr.



                                      - 7 -
<PAGE>

   Signature                        Title                           Date


/s/ Mark D. Ein
------------------------           Director                   November 18, 1999
Mark D. Ein


/s/ Rahul C. Prakash
------------------------           Director                   November 18, 1999
Rahul C. Prakash


/s/ Janice M. Roberts
------------------------           Director                   November 18, 1999
Janice M. Roberts


/s/ Rajendra Singh
------------------------           Director                   November 18, 1999
Dr. Rajendra Singh


/s/ George P. Stamas
------------------------           Director                   November 18, 1999
George P. Stamas


/s/ Devin N. Wenig
------------------------           Director                   November 18, 1999
Devin N. Wenig


/s/ Thomas E. Wheeler
------------------------           Director                   November 18, 1999
Thomas E. Wheeler


                                      - 8 -
<PAGE>


                                  EXHIBIT INDEX


Exhibit
Number    Description
_____________________

4.1       1999 Equity Incentive Plan

5         Opinion of Wilmer, Cutler & Pickering as to the legality of the
          securities being registered

23.1      Consent of KPMG LLP

23.2      Consent of PricewaterhouseCoopers LLP

24        Power of attorney (included on signature pages of this Registration
          Statement)

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



                                      - 9 -
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 20107}]
{"company-data": {"conformed-name": "AETHER SYSTEMS LLC", "cik": "0001093434", "assigned-sic": "7373", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-91369", "film-number": "99761542"}, "business-address": {"street1": "11460 CRONRIDGE DRIVE", "city": "OWINGS MILLS", "state": "MD", "zip": "21117"}, "mail-address": {"street1": "11460 CRONRIDGE DRIVE", "city": "OWINGS MILLS", "state": "MD", "zip": "21117"}}
As filed with the Securities and Exchange Commission on November 19, 1999

                                            Registration No. 333_______________

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

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                    Form S-8
                             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 of                            (I.R.S. employer
 incorporation or organization)                         identification number)

                              11460 Cronridge Drive
                          Owings Mills, Maryland 21117
                    (Address of Principal Executive Offices)

                                 (410) 654-6400
              (Registrant's telephone number, including area code)

                              Aether Systems, Inc.
                           1999 Equity Incentive Plan
                            (Full title of the plan)

                                  David S. Oros
                             Chairman of the Board,
                       Chief Executive Officer & President

                              Aether Systems, Inc.
                              11460 Cronridge Drive
                          Owings Mills, Maryland 21117
                                 (410) 654-6400
          (Name and address, including zip code, and telephone number,
                   including area code, of agent for service)

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

                                 With a copy to:

                             R. Scott Kilgore, Esq.
                           Wilmer, Cutler & Pickering
                               2445 M Street, N.W.
                             Washington, D.C. 20037

                           ---------------------------
CALCULATION OF REGISTRATION FEE
Proposed           Proposed
                               Title of                                    Maximum            Maximum
                              Securities                  Amount          Offering           Aggregate          Amount of
                                to be                     to be            Price             Offering        Registration
         Name of Plan         Registered                Registered       Per Share (1)        Price (1)           Fee (1)
------------------------------------------------------------------------------------------------------------------------------------
1999 Equity Incentive     Common Stock, par $0.01       5,400,000          $31.98          $172,690,096         $48,008
Plan (the "1999 Plan")
------------------------------------------------------------------------------------------------------------------------------------
(1) In accordance with Rule 457(h) and Rule 457(c) the aggregate offering price and the amount of the registration fee are
    computed on the basis of (a) for 2,481,091 shares not yet subject to options, $66.69, the average of the high and low
    prices reported in the Nasdaq Stock Market on November 12, 1999, and (b) for granted options for 2,918,959 shares, the
    actual exercise prices specified in those granted options (which range from $0.40 to $8.00.) Also registered hereunder
    are such additional number of shares of Common Stock, presently indeterminable, as may be necessary to satisfy the
    antidilution provisions of the Plan to which this Registration Statement relates.
- 2 -
PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

                  Note: The document(s)  containing the information  required by
Item 1 of Form S-8 and the statement of availability  of registrant  information
and any other  information  required by Item 2 of Form S-8 will be sent or given
to  participants  as specified by Rule 428 under the  Securities Act of 1933, as
amended (the "Securities Act"). In accordance with Rule 428 and the requirements
of Part I of Form S-8, such documents are not being filed with the SEC either as
part of this Registration Statement or as prospectuses or prospectus supplements
pursuant  to Rule 424  under the  Securities  Act.  Aether  Systems,  Inc.  (the
"Registrant"  or the  "Company")  shall  maintain  a file of such  documents  in
accordance with the provisions of Rule 428. Upon request,  the Registrant  shall
furnish the SEC or its staff a copy or copies of all of the  documents  included
in such file.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

                  The Company  hereby  incorporates  by reference  the documents
listed in (a) through (c) below. In addition,  all documents  subsequently filed
by the Company pursuant to Section 13(a),  13(c), 14 and 15(d) of the Securities
Exchange  Act of 1934,  as amended  (the  "Exchange  Act") (prior to filing of a
Post-Effective  Amendment which indicates that all securities  offered have been
sold or which  deregisters all securities then remaining unsold) shall be deemed
to be incorporated by reference in this Registration  Statement and to be a part
hereof from the date of filing of such documents.

         (a) Prospectus on Form 424B4 filed by the Company on October 21, 1999.

         (b) The Company's Registration Statement on Form S-1 (SEC No.333-85697
             filed by the Company on August 20, 1999 and all amendments
             thereafter.

         (c) The   description   of  the  Company's   Common  Stock  which  is
             incorporated by reference from the Prospectus on Form 424B4 filed
             by the Company on October 21, 1999,  including  any  amendment or
             report filed for the purpose of updating such description.

Item 4. Description of Securities

           Not Applicable

Item 5.   Interests of Named Experts and Counsel

                  The validity of the shares of Company Common Stock that may be
issued under  options  granted  under the 1999 Plan is being passed upon for the
Company by Wilmer,  Cutler & Pickering.  George P. Stamas, a member of the Board
of Directors, is a partner in Wilmer, Cutler & Pickering. As of the date of this
Registration Statement,  Mr. Stamas had received stock options to purchase
23,850 shares of Common Stock and he holds a non-voting interest in  Telcom-ATI
Investors.

                                      - 3 -
Item 6.   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  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   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.

                  Prior to the  effective  date of the  Registration  Statement,
Aether will have entered into  agreements  with its directors and certain of its
executive  officers that require Aether to indemnify  such persons  against II-1
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
maybe  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 intends to obtain in conjunction with the effectiveness
of the  Registration  Statement 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.

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

Item 7.   Exemption from Registration Claimed

          Not Applicable.

                                      - 4 -
Item 8.   Exhibits

The Exhibit Index attached to this Registration Statement is incorporated herein
by reference.

Item 9.   Undertakings

(a)       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;

                           (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;

                           (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 (a)(1)(i) and (a)(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 by the registrant pursuant to section
                    13  or  section   15(d)  of  the   Exchange   Act  that  are
                    incorporated by reference in the 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.

(b)       The undersigned  Registrant  hereby  undertakes  that, for purposes of
          determining any liability under the Securities Act, each filing of the
          Registrant's  annual report pursuant to section 13(a) or section 15(d)
          of the  Exchange  Act  (and,  where  applicable,  each  filing  of any
          employee benefit plan's annual report pursuant to section 15(d) of the
          Exchange Act) that is incorporated  by reference in this  Registration
          Statement shall be deemed to be a new registration statement reflating
          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.

                                      - 5 -
(c)       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
          SEC such  indemnification is against public policy as expressed in the
          Securities Act and is, therefore,  unenforceable.  In 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
          of whether  such  indemnification  by it is against  public  policy as
          expressed  in the  Securities  Act and will be  governed  by the final
          adjudication of such issue.

            [The remainder of this page is intentionally left blank.]

                                      - 6 -
SIGNATURES

                  Pursuant to the  requirements  of the  Securities Act of 1933,
the Company  certifies that it has  reasonable  grounds to believe that it meets
all of the  requirements  for  filing  on  Form  S-8 and has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in Owings Mill, Maryland on the 18th day of November, 1999.

                                                AETHER SYSTEMS, INC.

                                                By:  /s/ David S. Oros
                                                -------------------------------
                                                David S. Oros
                                                Chief Executive Office

                                POWER OF ATTORNEY

KNOW ALL MEN BY THESE PRESENTS,  that each person whose signature  appears below
under the heading  "Signature"  constitutes and appoints David S. Oros and David
C.  Reymann as his or her true and lawful  attorney-in-fact  each acting  alone,
with full power of substitution and resubstitution, for him or her and in his or
her  name,  place  and  stead,  in any and  all  capacities  to sign  any or all
amendments (including post-effective amendments) to this Registration Statement,
and to file  the  same,  with all  exhibits  thereto,  and  other  documents  in
connection therewith, with the Securities and Exchange Commission, granting unto
said  attorney-in-fact full power and authority to do and perform each and every
act and thing  requisite and necessary to be done in and about the premises,  as
fully for all  intents  and  purposes  as he or she might or could do in person,
hereby  ratifying and confirming all that said  attorney-in-fact,  or his or her
substitute, acting alone, may lawfully do or cause to be done by virtue hereof.

         Pursuant  to the  requirements  of the  Securities  Act of  1933,  this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities and on the dates indicated.

    Signature                            Title                      Date

                                Chairman of the Board,
/s/ David S. Oros               Chief Executive Officer
------------------------        and President                 November 18, 1999
David S. Oros

/s/ David C. Reymann
------------------------        Chief Financial Officer       November 18, 1999
David C. Reymann

/s/ J. Carter Beese, Jr.
------------------------        Director                      November 18, 1999
J. Carter Beese, Jr.

/s/ Frank A. Bonsal, Jr.
------------------------        Director                      November 18, 1999
Frank A. Bonsal, Jr.

                                      - 7 -
Signature                        Title                           Date

/s/ Mark D. Ein
------------------------           Director                   November 18, 1999
Mark D. Ein

/s/ Rahul C. Prakash
------------------------           Director                   November 18, 1999
Rahul C. Prakash

/s/ Janice M. Roberts
------------------------           Director                   November 18, 1999
Janice M. Roberts

/s/ Rajendra Singh
------------------------           Director                   November 18, 1999
Dr. Rajendra Singh

/s/ George P. Stamas
------------------------           Director                   November 18, 1999
George P. Stamas

/s/ Devin N. Wenig
------------------------           Director                   November 18, 1999
Devin N. Wenig

/s/ Thomas E. Wheeler
------------------------           Director                   November 18, 1999
Thomas E. Wheeler

                                      - 8 -
EXHIBIT INDEX

Exhibit
Number    Description
_____________________

4.1       1999 Equity Incentive Plan

5         Opinion of Wilmer, Cutler & Pickering as to the legality of the
          securities being registered

23.1      Consent of KPMG LLP

23.2      Consent of PricewaterhouseCoopers LLP

24        Power of attorney (included on signature pages of this Registration
          Statement)

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

                                      - 9 -