<PAGE>

                                                                   EXHIBIT 10.36

                                                                  Execution Copy

                      COLLATERAL AGENCY, SUBORDINATION AND
                             INTERCREDITOR AGREEMENT

     THIS COLLATERAL AGENCY, SUBORDINATION AND INTERCREDITOR AGREEMENT (this
"Agreement"), dated as of March 16, 2004, is made by and among MOTIENT
COMMUNICATIONS, INC., a Delaware corporation (the "Company"), MOTIENT LICENSE
INC., a Delaware corporation ("License"), M&E ADVISORS L.L.C., a Delaware
limited liability corporation, (in its individual capacity, "M&E," and in its
capacity as Collateral Agent, the "Collateral Agent"), and MOTOROLA, INC., a
Delaware corporation ("Motorola").

                                   WITNESSETH:

     WHEREAS, the Company has entered into that certain Amended and Restated
Term Credit Agreement dated as of January 27, 2003 by and among the Company,
Motient Corporation, a Delaware corporation, Motient Holdings Inc., a Delaware
corporation, M&E and each of the other lenders party thereto, as amended by
Amendment No. 1 to Amended and Restated Term Credit Agreement dated March 16,
2004 (and as the same may be further amended, the "M&E Credit Agreement"). In
order to secure the obligations under the M&E Credit Agreement, the Company has
executed that certain Motient Communications Share Pledge Agreement dated as of
March 16, 2004 (the "M&E Pledge Agreement"), pledging a security interest in the
collateral described on Exhibit A attached hereto (the "Collateral");

     WHEREAS, the Company has also executed that certain SLA Promissory Note
dated as of December 1, 2002 in the original principal amount of $2,618,555.11
in favor of Motorola, as amended by the Motorola Amendment defined below (the
"SLA Note") and has entered into that certain Credit Agreement dated as of June
17, 1998 by and between ARDIS Company, predecessor to the Company, and Motorola,
as amended by Amendment No. 1 to Credit Agreement dated as of October 15, 1998,
Amendment No. 2 to Credit Agreement dated as of September 1, 2000 as further
amended by Assumption Release Agreement and Waiver Agreement dated as of
December 29, 2000 and the Settlement and Release Agreement, dated as of January
17, 2003, by and among the Company, Motient Corporation, Motorola and Motorola
Credit Corporation (as amended by the Motorola Amendment defined below the
"Motorola Credit Agreement"). The SLA Note and the Motorola Credit Agreement
have been amended by that certain Amendment to SLA Note and Credit Agreement
dated as of March 16, 2004 (the "Motorola Amendment"). In order to secure the
SLA Note and the Motorola Credit Agreement, the Company has executed that
certain Subordinate Motient Communications Share Pledge Agreement dated as of
March 16, 2004 (the "Motorola Pledge Agreement"), pledging a security interest
in the Collateral, which security interest is subordinate to the security
interest pledged pursuant to the M&E Pledge Agreement in accordance with this
Agreement;

     WHEREAS, it is a condition precedent to the execution and delivery of the
M&E Pledge Agreement and the Motorola Pledge Agreement (collectively, the
"Pledge Agreements") that the parties hereto enter into this Agreement for the
purpose of appointing M&E as Collateral Agent under the Pledge Agreements; and


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<PAGE>

    WHEREAS, M&E and Motorola desire to enter into this Agreement for the
purpose of regulating their respective rights and interests with respect to the
Collateral, to appoint M&E as Collateral Agent and to set forth its duties and
responsibilities as Collateral Agent hereunder;

     NOW, THEREFORE, in consideration of the foregoing premises and the
agreements, provisions and covenants herein, the parties hereby agree as
follows:

     1. RECITALS.

     The recitals to this Agreement are hereby incorporated into this Agreement
for all purposes.

     2. DEFINITIONS.

     Capitalized terms used herein and not otherwise defined shall have the
meaning ascribed thereto in the Pledge Agreements. For the purposes of this
Agreement the following terms shall have the following meanings specified with
respect thereto below:

     "Agreement" shall mean this Collateral Agency, Subordination and
Intercreditor Agreement, as the same may be amended and in effect from time to
time.

     "Collateral" shall have the meaning given in the recitals.

     "Credit Documents" shall mean, collectively, the M&E Credit Agreement, the
M&E Pledge Agreement, the SLA Note, the Credit Note, the Motorola Credit
Agreement and the Motorola Pledge Agreement, and all other relevant agreements
and instruments executed by the Company in connection therewith.

     "Credit Note" shall mean that certain Amended and Restated Promissory Note
dated June 17, 1998, as amended and restated as of September 1, 2000, as further
amended and restated as of December 29, 2000 and as further amended by Amendment
No. 1, dated January 17, 2003, in the original principal amount of $15,000,000
by the Company in favor of Motorola issued in connection with the Credit
Agreement.

     "M&E Obligations" shall mean any and all Secured Obligations as such term
is defined in the M&E Pledge Agreement.

     "Motorola Obligations" shall mean any and all Secured Obligations as such
term is defined in the Motorola Pledge Agreement.

     "Proceeds" shall mean the proceeds of any collection, sale, transfer,
assignment or other liquidation or disposition of any of Collateral which are
received in the form of cash or other immediately available funds.

     "Secured Parties" shall mean both M&E and Motorola and their respective
successors and assigns.


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<PAGE>

     3. COLLATERAL AGENCY; SUBORDINATION

     (a) Appointment of the Collateral Agent . Both of the Secured Parties
hereby irrevocably designate and appoint M&E as the Collateral Agent under this
Agreement for the purpose of holding and possessing all of the shares and
securities comprising the Collateral for the benefit of the Secured Parties and
in order that the security interests created under the Pledge Agreements will be
perfected, including all certificates evidencing such shares and securities, and
each such Secured Party irrevocably authorizes Collateral Agent to take such
action or refrain from taking action, as provided under the provisions of this
Agreement and the Security Documents and to exercise such powers and perform
such duties as are expressly delegated to the Collateral Agent, by the terms of
this Agreement, together with such other powers as are reasonably incidental
thereto.

     (b) Subordination. Both of the Secured Parties hereby acknowledge and agree
that all security interests created by the Motorola Pledge Agreement on any of
the Collateral are expressly subordinate to all security interests created by
the M&E Pledge Agreement regardless of (i) M&E's acting as Collateral Agent
hereunder for both of the Secured Parties, (ii) the failure of any party to make
proper and timely filings of recordation, (iii) the place or timing of any
filing or recordation, (iv) the timing or amount of any disbursement or advance
under either the M&E Obligations or the Motorola Obligations, or (v) any other
reason.

     (c) Limitation on Collateral Agent's Duties and Liabilities in Respect of
the Collateral .

          (i)  Notwithstanding any provision elsewhere to the contrary in this
               Agreement or any other Credit Document, the Collateral Agent
               shall have only those duties or responsibilities expressly set
               forth herein and therein, and in the exercise thereof, the
               Collateral Agent agrees to use the same degree of care and skill
               as a prudent person would exercise or use under the circumstances
               in the conduct of his own affairs. Except as otherwise expressly
               provided herein, the Collateral Agent shall not have any duty or
               liability to the Company or any affiliate thereof or to the
               Secured Parties as to any Collateral in its possession or control
               or in the possession or control of any of its agents or nominees
               (including, without limitation, any Proceeds thereof), or any
               income thereon or to the preservation of rights against prior
               parties or any other rights pertaining thereto.

          (ii) Neither the Collateral Agent nor any of its officers, directors,
               employees or agents shall be (a) liable for any action lawfully
               taken or omitted to be taken by such Collateral Agent or its
               officers, directors, employees or agents, under or in connection
               with this Agreement or any other Credit Document (except for its
               or such individual or entity's own gross negligence or willful
               misconduct), or (b) responsible in any manner for any recitals,
               statements, representations or warranties contained in this
               Agreement, any other Credit Document or in any certificate,
               report, statement or other document referred to or provided for
               in, or, received by the Collateral Agent under or in connection
               with, this Agreement or any other Credit Document or for the
               value, validity, effectiveness,


                                       3
<PAGE>

               genuineness, enforceability or sufficiency of this Agreement or
               any other Credit Document or for any failure of the Company or
               the Secured Parties to perform its or their obligations hereunder
               or thereunder or for any calculations required hereunder or
               thereunder.

          (iii) The Collateral Agent may execute any of its duties as agent
               hereunder by or through agents or employees. Before taking any
               action hereunder or refraining from taking any action hereunder,
               the Collateral Agent shall be entitled to retain experts
               (including counsel which may be counsel to the Company or other
               counsel of its own choosing) and to act in reliance upon the
               written advice of such experts concerning all matters pertaining
               to the agencies hereby created and its duties hereunder, and
               shall not be liable for any action taken or omitted to be taken
               by any agent selected with reasonable care or by it in good faith
               in accordance with the written advice of such experts selected by
               it with reasonable care. In the performance of its duties
               hereunder the Collateral Agent shall act in accordance with its
               discretion as provided herein.

          (iv) Neither the Collateral Agent nor either Secured Party, nor any of
               its or their respective directors, officers, employees or agents,
               shall be liable to any other Secured Party or the Company for any
               action taken or omitted to be taken by it or them hereunder or in
               connection herewith, except for its or their own gross negligence
               or willful misconduct, nor shall the Collateral Agent be
               responsible to any Secured Party for the validity, effectiveness,
               value, sufficiency or enforceability of this Agreement, any other
               Security Document furnished pursuant hereto or in connection
               herewith, or of the Collateral (or any part thereof).

     (d) Fees and Expenses.

          (i)  The Company agrees to pay to the Collateral Agent, from time to
               time upon demand, the reasonable costs and out-of-pocket expenses
               of the Collateral Agent (including, without limitation, the
               reasonable fees and disbursements of counsel, professional
               consultants and agents employed or engaged by the Collateral
               Agent (including, without limitation, fees, costs and expenses
               incurred in connection with any proceedings under any bankruptcy,
               reorganization, compromise, arrangement, insolvency,
               restructuring, debt dissolution or liquidation or similar how
               which fees, costs and expenses shall constitute administrative
               expenses in any such proceeding)), (i) incurred in connection
               with the development, preparation and execution of, and any
               amendment, supplement or modification to, this Agreement, the
               other Credit Documents and any other documents prepared in
               connection herewith or therewith, and the consummation of the
               transactions contemplated hereby and thereby, including, without
               limitation, the fees and disbursements of counsel and
               professional consultants to the Collateral Agent, (ii) arising in
               connection with the administration of this Agreement or any other
               Credit Document or the enforcement of any of the provisions
               hereof or thereof, or (iii) incurred or required to be advanced
               in connection with (A) the administration of the Collateral, (B)


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<PAGE>

               any advance made by the Collateral Agent on behalf of the Company
               under any Credit Document, (C) the sale or other disposition of
               Collateral pursuant to any Credit Document and (D) the
               enforcement, preservation, protection or defense of the rights of
               the Collateral Agent under this Agreement and the other Credit
               Documents and in and to the Collateral.

          (ii) Without limiting the obligations of the Company under this
               paragraph, the Company agrees to pay or to reimburse the
               Collateral Agent for any and all payments made by the Collateral
               Agent in respect of any search, filing, recording and
               registration fees, taxes, excise taxes and other similar imposts
               which may be payable or determined to be payable in respect of
               the execution and delivery of, or consummation of any of the
               transactions contemplated by, or any amendment, supplement or
               modification of, or any waiver or consent under or in respect of,
               this Agreement and the other Credit Documents.

          (iii) The obligations of the Company under this Section 3(d) shall
               survive the termination of the other provisions of this
               Agreement.

     (e) Indemnification of the Collateral Agent.

          (i)  The Company agrees to indemnify and hold harmless the Collateral
               Agent from and against any and all claims, demands, losses,
               judgments and liabilities (including liabilities for penalties)
               of whatsoever kind or nature, and to reimburse the Collateral
               Agent for any and all costs and expenses, including reasonable
               attorneys' fees and expenses, (i) with respect to, or resulting
               from, any delay in paying, any and all excise, sales or other
               taxes which may be payable or determined to be payable with
               respect to any of the Collateral, (ii) with respect to, or
               resulting from, any strict liability arising from or failure to
               comply with, or delay in complying with, any law applicable to
               any of the Collateral, or (iii) relating to, growing out of or
               resulting from this Agreement or any other Credit Document or the
               enforcement of any provision of this Agreement or any other
               Credit Document or the exercise by the Collateral Agent of any
               right or remedy granted to it hereunder or thereunder; provided,
               however, that the Collateral Agent shall not be indemnified if it
               has been grossly negligent or guilty of willful misconduct with
               respect to such exercise. If and to the extent that the
               obligations of the Company under this Section 3(e) are
               unenforceable for any reason, the Company hereby agrees to make
               the maximum contribution to the payment and satisfaction of such
               obligations permissible under applicable law.

          (ii) The obligations of the Company under this Section 3(e) shall
               survive the termination of the other provisions of this Agreement
               or any termination that occurs under any bankruptcy law.


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<PAGE>

     (f) Adequate Provision. In the event the Company fails to pay amounts due
the Collateral Agent under Paragraphs (c) and (d) hereof, the Secured Parties
agree to reimburse the Collateral Agent for such amounts on a pro rata basis
based on the amount of the M&E Obligations and the Motorola Obligations.

     (g) Resignation of the Collateral Agent; Termination Agreement.

          (i)  The Collateral Agent may at any time, by giving written notice to
               the Company and the Secured Parties, resign and be discharged of
               the responsibilities created hereby and under the Security
               Documents, such resignation to become effective upon (i) the
               appointment of a successor Collateral Agent and (ii) the
               acceptance of such appointment by such successor Collateral
               Agent. As promptly as practicable after the giving of any such
               notice, M&E shall appoint a successor Collateral Agent. The
               Collateral Agent so resigned shall be entitled to any amounts due
               under subsections (c) and (d) of this Section 3 to the extent
               incurred or arising, or relating to events occurring, before such
               resignation or removal becomes effective.

          (ii) Following ninety (90) days after satisfaction in full of the M&E
               Obligations, this Agreement will terminate and M&E shall no
               longer act as Collateral Agent hereunder and shall deliver all of
               the Collateral in its possession to Motorola or, if the Motorola
               Obligations have been satisfied in full and Motorola has
               confirmed such satisfaction in writing, then to the Company.

     (h) Collateral Agent's Calculations . In making any determinations and
allocations required hereunder, the Collateral Agent may rely upon information
supplied by the Secured Parties as to the amounts payable with respect to the
Secured Obligations, absent manifest error, and the Collateral Agent, as such,
shall have no liability to the Company, its affiliates or any Secured Party for
actions taken in reliance on such information, except for its own gross
negligence or willful misconduct.

     4. COOPERATION AMONG PARTIES.

     (a) Cooperation. Each Secured Party agrees with each of the other Secured
Parties and the Collateral Agent that: (i) it will from time to time provide
such information to the Collateral Agent as may be necessary or reasonably
requested by it to enable such Collateral Agent to make any calculation
hereunder or otherwise required for any other purpose hereby, and (ii) it will
from time to time discuss with the Collateral Agent and the other Secured
Parties in good faith the enforcement of its rights with a view to recovering
amounts due under the M&E Obligations and the Motorola Obligations.

     (b) Amendments to Credit Documents.

          (i)  M&E agrees that prior to the termination of this Agreement, M&E
               may amend the M&E Credit Agreement and any of the other related
               documents, provided that no amendment shall be made by M&E to (i)


                                       6
<PAGE>

               increase the maximum principal amount of the M&E Obligations
               thereunder (ii) modify the date of required payments to make the
               date earlier or (iii) increase the rate of interest without, in
               each case, the prior written consent of Motorola.

          (ii) Motorola agrees that prior to termination of this Agreement,
               Motorola may amend the SLA Note, the Motorola Credit Agreement
               and any of the other related documents provided that no amendment
               will be made by Motorola that would (i) increase the amounts
               owed, (ii) modify the date of required payments so as to make
               such date earlier, or (iii) increase the rate of interest
               without, in each case, the prior written consent of M&E.

     5. RIGHTS OF SECURED PARTIES.

     (a) Rights of Secured Parties; Limitations on Institution of Suits . Except
as set forth in this Agreement or the other Credit Documents, the right of both
of the Secured Parties to receive payment of the M&E Obligations and the
Motorola Obligations, as applicable, held by such Secured Party when due
(whether at the stated maturity thereof, by acceleration or otherwise), and the
obligations of the Company to pay such M&E Obligations and the Motorola
Obligations when due, shall not be impaired or affected by the terms of this
Agreement or the other Credit Documents without the consent of such Secured
Party.

     (b) Indemnification of Secured Parties .

          (i)  The Company agrees to indemnify and hold harmless the Secured
               Parties from and against any and all claims, demands, losses,
               judgments and liabilities (including liabilities for penalties)
               of whatsoever kind or nature, and to reimburse the Secured
               Parties for all costs and expenses, including reasonable
               attorneys' fees and expenses, (i) with respect to, or resulting
               from, any delay in paying, any and all excise, sales or other
               taxes which may be payable or determined to be payable with
               respect to any of the Collateral, (ii) with respect to, or
               resulting from, any strict liability arising from or failure to
               comply with or delay in complying with any law applicable to any
               of the Collateral or (iii) relating to, growing out of or
               resulting from this Agreement or any other Credit Document or the
               enforcement of any provision of this Agreement or any other
               Credit Document or the exercise by the Secured Parties of any
               right or remedy granted to it hereunder or thereunder; provided,
               however, that no Secured Party shall be indemnified if it has
               been guilty of gross negligence or willful misconduct with
               respect to such exercise. If and to the extent that the
               obligations of the Company under this Paragraph 5(b) are
               unenforceable for any reason, the Company hereby agrees to make
               the maximum contribution to the payment and satisfaction of such
               obligations permissible under applicable law.

          (ii) The obligations of the Company under this Paragraph (b) shall
               survive the termination of the other provisions of this
               Agreement.


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<PAGE>

     (c) Notice and Cure.

          (i)  So long as the M&E Obligations remain unsatisfied, M&E agrees
               that in the event Company defaults under any provisions of the
               M&E Credit Agreement or any related document and such default
               remains uncured and unwaived, M&E will provide Motorola with
               written notice thereof prior to M&E commencing any Foreclosure
               proceeding and allow Motorola ten (10) days to cure Company's
               default; provided, however, M&E shall have the right to send
               notices of and to commence all proceedings necessary for
               Foreclosure of the Collateral during such ten (10) day period.

          (ii) So long as the Motorola Obligations remain unsatisfied, Motorola
               agrees that in the event Company defaults under any provision of
               the SLA Note, the Motorola Credit Agreement or any related
               document and such default remains uncured and unwaived, Motorola
               will provide M&E with written notice thereof prior to Motorola
               commencing any Foreclosure proceeding and allow M&E ten (10) days
               to cure Company's default; provided, however, Motorola shall have
               the right to send notices of and to commence all proceedings
               necessary for Foreclosure of the Collateral during such ten (10)
               day period. Motorola acknowledges that, following any Foreclosure
               conducted by Motorola, the purchaser at such Foreclosure shall
               own the Collateral subject to the security interests and other
               rights of M&E in and to the Collateral in accordance with the M&E
               Pledge Agreement.

          (iii) Notwithstanding anything to the contrary herein contained, no
               transfer of the assets of License (the "License Assets") by the
               Company, License or any of their respective affiliates to a third
               party that is (A) approved by M&E in its individual capacity or
               as Collateral Agent and (B) not M&E or any of its members or any
               of their respective affiliates (excluding any such transfers
               occurring in connection with a Foreclosure, which shall be
               permissible) shall constitute a default under the SLA Note, the
               Motorola Credit Agreement, the Motorola Amendment or the Motorola
               Pledge Agreement; provided that the Company shall promptly notify
               Motorola of any such transfers. Any direct or indirect transfer
               of all or any part of the License Assets to M&E or any of its
               members or any of their respective affiliates other than
               transfers relating to a Foreclosure shall require the prior
               written consent of Motorola.

     6. NO WAIVER; CUMULATIVE REMEDIES. Neither the Collateral Agent nor any
Secured Party shall by any act (except by a written instrument pursuant to
Paragraph 3 hereof), delay, indulgence, omission or otherwise, be deemed to have
waived any right or remedy hereunder or to have acquiesced in any default or in
any breach of any of the terms and conditions hereof. No failure to exercise,
nor any delay in exercising, on the part of the Collateral Agent or either
Secured Party, any right, power or privilege hereunder shall operate as a waiver
thereof. No single or partial exercise of any right, power or privilege
hereunder shall preclude any other or further exercise thereof or the exercise
of any other right, power or privilege. A waiver by the Collateral Agent or
either Secured Party of any right or remedy hereunder on anyone occasion shall


                                       8
<PAGE>

not be construed as a bar to any right or remedy which the Collateral Agent or
either Secured Party would otherwise have on any future occasion. The rights and
remedies herein provided are cumulative, may be exercised singly or concurrently
and are not exclusive of any rights or remedies provided by law.

     7. SEVERABILITY. Any provision of this Agreement which is prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective
to the extent of such prohibition or unenforceability without invalidating the
remaining provisions hereof, and any such prohibition or unenforceability in any
jurisdiction shall not invalidate or render unenforceable such provision in any
other jurisdiction.

     8. PARAGRAPH HEADINGS. The paragraph headings used in this Agreement are
for convenience of reference only and are not to affect the construction hereof
or be taken into consideration in the interpretation hereof.

     9. WAIVERS AND AMENDMENTS; SUCCESSORS AND ASSIGNS; GOVERNING LAW. None of
the terms or provisions of this Agreement may be waived, amended, supplemented
or otherwise modified unless the same shall be in writing and approved by the
Collateral Agent and the Secured Parties; and, provided, further, that any
amendments that relate to the obligations of the Company under this Agreement
shall require the approval of the Company. This Agreement shall be binding upon
the successors and assigns of the Company and shall inure to the benefit of the
Collateral Agent and the Secured Parties and their respective successors and
assigns. THIS AGREEMENT SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, AND
THE RIGHTS OF THE PARTIES GOVERNED BY, THE LAWS OF THE STATE OF ILLINOIS,
WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAWS.

     10. NOTICES. All notices, requests and demands or other communications
provided for hereunder shall be in writing, sent by certified or registered
first class mail, or nationwide overnight delivery service (with charges
prepaid), and (i) if to the Company, addressed to the Company at 300
Knightsbridge Parkway, Lincolnshire, Illinois 60069, Attention: General Counsel,
(ii) if to the Collateral Agent, to the Collateral Agent at c/o Romulus Holdings
Inc., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632, Attention: Gary Singer,
(iii) if to Motorola, addressed to them at 1303 East Algonquin Road, Schaumburg,
Illinois 60196, Attention: Debi Burmeister, or in each case, at such other
address as each party shall specify to the other party in writing.

     11. JUDICIAL PROCEEDINGS. The Company and the Collateral Agent each hereby
irrevocably submits itself to the jurisdiction of any Illinois state court or
any Federal court sitting in the State of Illinois for the purpose of any suit,
action or other proceeding arising out of, or relating to, this Agreement or the
subject matter hereof, and each of them hereby waives, and agrees not to assert,
by way of motion, as a defense or otherwise, in any such suit, action or
proceedings, (i) any claim that it is not personally subject to the jurisdiction


                                       9
<PAGE>

of the above-named courts for any reason whatsoever, that such suit, action or
proceeding is brought in an inconvenient forum or that the venue of such suit,
action or proceeding is improper and (ii) any right which it may have to a trial
by a jury.

     The Company hereby agrees that the submission to jurisdiction referred to
in this Paragraph shall not limit in any manner the rights of the Collateral
Agent or the Secured Parties to take proceedings against the Company in some
other court of competent jurisdiction whether within or outside the United
States.

     12. COUNTERPARTS. This Agreement may be executed simultaneously in two or
more counterparts, each of which shall be deemed an original, and it shall not
be necessary in making proof of this Agreement to produce or account for more
than one such counterpart.

     13. CONFLICTING AGREEMENTS. In the event of a conflict or ambiguity between
this Agreement and the terms of any other Credit Document, this Agreement shall
govern with respect to the rights, duties, obligations and immunities of the
Collateral Agent and the Secured Parties.

     14. TERMINATION. This Agreement shall terminate and be of no further force
and effect upon the earliest to occur of (i) termination in accordance with
Section 2(f)(ii), (ii) the termination of all of the Credit Documents in
accordance with their respective terms and (iii) the release of all Collateral
in accordance with the terms of the Credit Documents.

     THIS DOCUMENT CONTAINS A WAIVER OF TRIAL BY JURY. SEE PARAGRAPH 11 HEREOF.

                            [Signature Pages Follow]
















                                       10
<PAGE>




     IN WITNESS WHEREOF, each of the parties hereto has caused this Agreement to
be duly executed and delivered by their duly authorized officers as of the date
and year above first written.

                           PLEDGOR:

                           MOTIENT COMMUNICATIONS INC.


                           By: /s/ Christopher Downie
                           Name:  Christopher Downie
                           Title: Chief Financial Officer


                           COLLATERAL AGENT AND SECURED PARTY:

                           M&E ADVISORS L.L.C., as Collateral Agent and
                           Secured Party


                           By:  /s/ Gary Singer
                           Name: Gary Singer
                           Title: Investment Advisor


                           SECURED PARTY:

                           MOTOROLA, INC., as Secured Party


                           By:_____________________________
                           Name:
                           Title:







                   [Signature Page to Intercreditor Agreement]

<PAGE>


                           MOTOROLA, INC.



                           By: /s/ Gary B. Tatje
                           Name: Gary Tatje
                           Title:   Vice President








                  [Signature Page to Intercreditor Agreement]

<PAGE>


                                                                       EXHIBIT A


                                   Collateral


Motient License Inc.
Delaware corporation
1,000 shares of common stock, par value $0.01 per share, issued to Motient
      Communications Inc.