<PAGE>   1
                                                                   EXHIBIT 10.91

                                                                  EXECUTION COPY


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


                          PASS THROUGH TRUST AGREEMENT

                          Dated as of February 9, 1998

                                    between

                                ATLAS AIR, INC.

                                      and

                            WILMINGTON TRUST COMPANY

                                   as Trustee

                                  $300,254,000

                     Atlas Air Pass Through Trust 1998-1A-S


          7.38% Atlas Air 1998-1A-S Initial Pass Through Certificates
          7.38% Atlas Air 1998-1A-S Exchange Pass Through Certificates


--------------------------------------------------------------------------------
<PAGE>   2
                               TABLE OF CONTENTS


<TABLE>
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   <S>            <C>                                                                                                  <C>
                                                        ARTICLE I

                                                       DEFINITIONS

   Section 1.01.  Definitions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   Section 1.02.  Compliance Certificates and Opinions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  15
   Section 1.03.  Form of Documents Delivered to Trustee  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16
   Section 1.04.  Directions of Certificateholders  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  16

                                                        ARTICLE II

                                            ORIGINAL ISSUANCE OF CERTIFICATES:
                                              ACQUISITION OF TRUST PROPERTY

   Section 2.01.  Delivery of Documents; Delivery Dates   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  18
   Section 2.02.  Withdrawal of Deposits  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
   Section 2.03.  Acceptance by Trustee   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  19
   Section 2.04.  Limitation of Powers  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  20

                                                       ARTICLE III

                                                     THE CERTIFICATES

   Section 3.01.  Title, Form, Denomination and Execution of Certificates   . . . . . . . . . . . . . . . . . . . . .  20
   Section 3.02.  Restrictive Legends   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  22
   Section 3.03.  Authentication of Certificates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
   Section 3.04.  Transfer and Exchange   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  24
   Section 3.05.  Book-Entry Provisions for U.S. Global Certificate and Offshore Global Certificates  . . . . . . . .  25
   Section 3.06.  Special Transfer Provisions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  26
   Section 3.07.  Mutilated, Destroyed, Lost or Stolen Certificates   . . . . . . . . . . . . . . . . . . . . . . . .  29
   Section 3.08.  Persons Deemed Owners   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   Section 3.09.  Cancellation  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   Section 3.10.  Temporary Certificates  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   Section 3.11.  Limitation of Liability for Payments  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  31
</TABLE>
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                                                        ARTICLE IV

                                               DISTRIBUTIONS; STATEMENTS TO
                                                    CERTIFICATEHOLDERS

   Section 4.01.  Certificate Account and Special Payments Account  . . . . . . . . . . . . . . . . . . . . . . . . .  31
   Section 4.02.  Distributions from Certificate Account and Special Payments Account   . . . . . . . . . . . . . . .  32
   Section 4.03.  Statements to Certificateholders  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
   Section 4.04.  Investment of Special Payment Moneys  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35

                                                        ARTICLE V

                                                       THE COMPANY

   Section 5.01.  Maintenance of Corporate Existence  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
   Section 5.02.  Consolidation, Merger, Etc.   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  36

                                                        ARTICLE VI

                                                         DEFAULT

   Section 6.01.  Events of Default   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  37
   Section 6.02.  Incidents of Sale of Equipment Notes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
   Section 6.03.  Judicial Proceedings Instituted by Trustee; Trustee May Bring Suit  . . . . . . . . . . . . . . . .  40
   Section 6.04.  Control by Certificateholders   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
   Section 6.05.  Waiver of Past Defaults   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  41
   Section 6.06.  Right of Certificateholders to Receive Payments Not to Be Impaired  . . . . . . . . . . . . . . . .  42
   Section 6.07.  Certificateholders May Not Bring Suit Except Under Certain
                       Conditions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
   Section 6.08.  Remedies Cumulative   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
   Section 6.09.  Undertaking for Costs   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43

                                                       ARTICLE VII

                                                       THE TRUSTEE

   Section 7.01.  Certain Duties and Responsibilities   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  43
   Section 7.02.  Notice of Defaults  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
   Section 7.03.  Certain Rights of Trustee   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
</TABLE>





                                      ii
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   Section 7.04.  Not Responsible for Recitals or Issuance of Certificates  . . . . . . . . . . . . . . . . . . . . .  45
   Section 7.05.  May Hold Certificates   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Section 7.06.  Money Held in Trust   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Section 7.07.  Compensation and Reimbursement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  46
   Section 7.08.  Corporate Trustee Required; Eligibility   . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  47
   Section 7.09.  Resignation and Removal; Appointment of Successor   . . . . . . . . . . . . . . . . . . . . . . . .  47
   Section 7.10.  Acceptance of Appointment by Successor  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  49
   Section 7.11.  Merger, Conversion, Consolidation or Succession to Business   . . . . . . . . . . . . . . . . . . .  49
   Section 7.12.  Maintenance of Agencies   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  50
   Section 7.13.  Money for Certificate Payments to Be Held in Trust  . . . . . . . . . . . . . . . . . . . . . . . .  51
   Section 7.14.  Registration of Equipment Notes in Trustee's Name   . . . . . . . . . . . . . . . . . . . . . . . .  51
   Section 7.15.  Representations and Warranties of Trustee   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  52
   Section 7.16.  Withholding Taxes; Information Reporting  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  53
   Section 7.17.  Trustee's Liens   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  53
   Section 7.18.  Preferential Collection of Claims   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  53

                                                       ARTICLE VIII

                                     CERTIFICATEHOLDERS' LISTS AND REPORTS BY TRUSTEE

   Section 8.01.  The Company to Furnish Trustee with Names and Addresses of Certificateholders   . . . . . . . . . .  54
   Section 8.02.  Preservation of Information; Communications to Certificateholders   . . . . . . . . . . . . . . . .  54
   Section 8.03.  Reports by Trustee  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54
   Section 8.04.  Reports by the Company  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  54

                                                        ARTICLE IX

                                                 SUPPLEMENTAL AGREEMENTS

   Section 9.01.  Supplemental Agreements Without Consent of Certificateholders   . . . . . . . . . . . . . . . . . .  55
   Section 9.02.  Supplemental Agreements with Consent of Certificateholders  . . . . . . . . . . . . . . . . . . . .  57
   Section 9.03.  Documents Affecting Immunity or Indemnity   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
   Section 9.04.  Execution of Supplemental Agreements  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
   Section 9.05.  Effect of Supplemental Agreements   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  58
   Section 9.06.  Conformity with Trust Indenture Act   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59
   Section 9.07.  Reference in Certificates to Supplemental Agreements  . . . . . . . . . . . . . . . . . . . . . . .  59
</TABLE>





                                     iii
<PAGE>   5
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                                                        ARTICLE X

                                        AMENDMENTS TO INDENTURE AND NOTE DOCUMENTS

   Section 10.01.  Amendments and Supplements to Indenture and Other Note
                       Documents  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  59

                                                        ARTICLE XI

                                                  TERMINATION OF TRUSTS

   Section 11.01.  Termination of the Trust   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  60

                                                       ARTICLE XII

                                                 MISCELLANEOUS PROVISIONS

   Section 12.01.  Limitation on Rights of Certificateholders   . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
   Section 12.02.  Liabilities of Certificateholders  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
   Section 12.03.  Registration of Equipment Notes in Name of Subordination Agent   . . . . . . . . . . . . . . . . .  63
   Section 12.04.  Notices  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  63
   Section 12.05.  Governing Law  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
   Section 12.06.  Severability of Provisions   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  64
   Section 12.07.  Trust Indenture Act Controls   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.08.  Effect of Headings and Table of Contents   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.09.  Successors and Assigns   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.10.  Benefits of Agreement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.11.  Legal Holidays   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.12.  Counterparts   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  65
   Section 12.13.  Communication by Certificateholders with Other Certificateholders  . . . . . . . . . . . . . . . .  65
   Section 12.14.  Intention of Parties   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  66
</TABLE>





                                      iv

<PAGE>   6

Reconciliation and tie between Atlas Air Pass Through Trust Agreement, dated as
of February 9, 1998 and the Trust Indenture Act of 1939.  This reconciliation
does not constitute part of the Pass Through Trust Agreement.

<TABLE>
<CAPTION>
                          Trust Indenture Act                                Pass Through Trust
                            of 1939 Section                                   Agreement Section
           ------------------------------------------------   ------------------------------------------------
                              <S>                                                 <C>
                              310(a)(1)                                           7.07
                                 (a)(2)                                           7.07
                              312(a)                                              3.05; 8.01; 8.02
                              313(a)                                              7.07

                              314(a)                                              8.04(a) - (c)
                                 (a)(4)                                           8.04(d)
                                 (c)(1)                                           1.02
                                 (c)(2)                                           1.02
                                 (d)(1)                                           7.13; 11.01
                                 (d)(2)                                           7.13; 11.01
                                 (d)(3)                                           2.01
                                 (e)                                              1.02
                              315(b)                                              7.02
                              316(a)(last sentence)                               1.01(c)
                                 (a)(1)(A)                                        6.04
                                 (a)(1)(B)                                        6.05
                                 (b)                                              6.06
                                 (c)                                              1.04(d)
                              317(a)(1)                                           6.03
                                 (b)                                              7.13
                              318(a)                                              12.05

</TABLE>



                                      v
<PAGE>   7
                          PASS THROUGH TRUST AGREEMENT

                 This PASS THROUGH TRUST AGREEMENT, dated as of February 9,
1998 (as the same may be amended, supplemented or modified from time to time,
this "Agreement"), between ATLAS AIR, INC., a Delaware corporation (the
"Company"), and WILMINGTON TRUST COMPANY, a Delaware trust company, as Trustee,
is made with respect to the formation of Atlas Air Pass Through Trust 1998-1A-S
and the deemed issuance of 7.38% Atlas Air 1998-1A-S Initial Pass Through
Certificates representing fractional undivided interests in the Trust.

                              W I T N E S S E T H:

                 WHEREAS, the Company has obtained commitments from Boeing
(such term and certain other capitalized terms used herein are defined below)
for the delivery of certain Aircraft;

                 WHEREAS, the Company as of the Transfer Date (as defined
below) the Company will have financed the acquisition of all or a portion of
such Aircraft either (i) through separate leveraged lease transactions, in
which case the Company leases such Aircraft (collectively, the "Leased
Aircraft") or (ii) through separate secured loan transactions, in which case
the Company owns such Aircraft (collectively, the "Owned Aircraft");

                 WHEREAS, as of the Transfer Date in the case of each Leased
Aircraft, each Owner Trustee, acting on behalf of the corresponding Owner
Participant, will have issued pursuant to an Indenture, on a non-recourse
basis, Equipment Notes in order to finance a portion of its purchase price of
such Leased Aircraft;

                 WHEREAS, as of the Transfer Date in the case of each Owned
Aircraft, the Company will have issued pursuant to an Indenture, on a recourse
basis, Equipment Notes to finance a portion of the purchase price of such Owned
Aircraft;

                 WHEREAS, as of the Transfer Date, the Related Trustee will
assign, transfer and deliver all of such trustee's right, title and interest to
the trust property held by the Related Trustee to the Trustee pursuant to the
Assignment and Assumption Agreement (as defined below);

                 WHEREAS, the Trustee, effective only, but automatically, upon
execution and delivery of the Assignment and Assumption Agreement, will be
deemed to have delared the creation of the Atlas Air Pass Through Trust 1998-1S
(the "Trust") for the benefit of the Certificateholders, and each Holder of
Certificates outstanding as of the Transfer Date, as a  grantor of the Trust,
by its respective acceptance of such Certificates, will join in the creation of
this Trust with the Trustee;
<PAGE>   8
                                       2

                 WHEREAS, all Certificates deemed issued by the Trust will
evidence fractional undivided interests in the Trust and will convey no rights,
benefits or interests in respect of any property other than the Trust Property
except for those Certificates to which an Escrow Receipt has been affixed;

                 WHEREAS, to facilitate the sale of Equipment Notes to, and the
purchase of Equipment Notes by, the Trustee on behalf of the Trust, the Company
has duly authorized the execution and delivery of this Agreement as the
"issuer", as such term is defined in and solely for purposes of the Securities
Act, of the Certificates to be issued pursuant hereto and as the "obligor", as
such term is defined in and solely for purposes of the Trust Indenture Act of
1939, as amended, with respect to all such Certificates and is undertaking to
perform certain administrative and ministerial duties hereunder and is also
undertaking to pay the ongoing fees and expenses of the Trustee;

                 WHEREAS, upon the execution and delivery of the Assignment and
Assumption Agreement, all of the conditions and requirements necessary to make
this Agreement, when duly executed and delivered, a valid, binding and legal
instrument in accordance with its terms and for the purposes herein expressed,
have been done, performed and fulfilled, and the execution and delivery of this
Agreement in the form and with the terms hereof have been in all respects duly
authorized;

                 WHEREAS, upon issuance of the Exchange Certificates, if any,
or the effectiveness of the Shelf Registration Statement, this Agreement as
amended or supplemented from time to time, will be subject to the provisions of
the Trust Indenture Act of 1939, as amended, and shall, to the extent
applicable, be governed by such provisions;

                 NOW, THEREFORE, in consideration of the mutual agreements
herein contained, and of other good and valuable consideration the receipt and
adequacy of which are hereby acknowledged, the parties hereto agree as follows:


                                   ARTICLE I

                                  DEFINITIONS

                 Section 1.01.  Definitions.  For all purposes of this
Agreement, except as otherwise expressly provided or unless the context
otherwise requires:

                 (a)      the terms used herein that are defined in this
         Article I have the meanings assigned to them in this Article I, and
         include the plural as well as the singular;
<PAGE>   9
                                       3

                 (b)      all other terms used herein which are defined in the
         Trust Indenture Act, either directly or by reference therein, or by
         the rules promulgated under the Trust Indenture Act, have the meanings
         assigned to them therein;

                 (c)      all references in this Agreement to designated
         "Articles", "Sections", "Subsections" and other subdivisions are to
         the designated Articles, Sections, Subsections and other subdivisions
         of this Agreement;

                 (d)      the words "herein", "hereof" and "hereunder" and
         other words of similar import refer to this Agreement as a whole and
         not to any particular Article, Section, Subsection or other
         subdivision; and

                 (e)      unless the context otherwise requires, whenever the
         words "including" "include" or "includes" are used herein, it shall be
         deemed to be followed by the phrase "without limitation".

                 "Act" has the meaning, with respect to any Certificateholder,
         specified in Section 1.04(a).

                 "Affiliate" means, with respect to any specified Person, any
         other Person directly or indirectly controlling or controlled by or
         under direct or indirect common control with such Person.  For the
         purposes of this definition, "control", when used with respect to any
         specified Person, means the power, directly or indirectly, to direct
         the management and policies of such Person, whether through the
         ownership of voting securities or by contract or otherwise, and the
         terms "controlling" and "controlled" have meanings correlative to the
         foregoing.

                 "Agent Members" has the meaning specified in Section 3.05(a).

                 "Agreement" has the meaning specified in the recitals hereto.

                 "Aircraft" means each of the Aircraft or Substitute Aircraft
         in respect of which a Participation Agreement is entered into in
         accordance with the Note Purchase Agreement.

                 "Assignment and Assumption Agreement" means the assignment and
         assumption agreement substantially in the form of Exhibit E to the
         Related Pass Through Trust Agreement executed and delivered in
         accordance with Section 11.01.

                 "Authorized Agent" means, with respect to the Certificates,
         any Paying Agent or Registrar for the Certificates.
<PAGE>   10
                                       4

                 "Avoidable Tax" has the meaning set forth in Section 7.09(e).

                 "Boeing" means The Boeing Company.

                 "Business Day" means, with respect to the Certificates, any
         day other than a Saturday, a Sunday or a day on which commercial banks
         are required or authorized to close in Denver, Colorado, New York, New
         York, Chicago, Illinois or, so long as any Certificate is outstanding,
         the city and state in which the Trustee or any related Loan Trustee
         maintains its Corporate Trust Office or receives and disburses funds.

                 "Certificate" means any one of the Initial Certificates or
         Exchange Certificates and any such Certificates issued in exchange
         therefor or replacement thereof pursuant to this Agreement.

                 "Certificate Account" means, with respect to the Certificates,
         the account or accounts created and maintained for such series
         pursuant to Section 4.01(a).

                 "Certificateholder" or "Holder" means the Person in whose name
         a Certificate is registered in the Register for Certificates.

                 "Clearing Agency" means an organization registered as a
         "clearing agency" pursuant to Section 17A of the Securities Exchange
         Act of 1934, as amended.

                 "Clearing Agency Participant" means a broker, dealer, bank,
         other financial institution or other Person for whom from time to time
         a Clearing Agency effects, directly or indirectly, book-entry
         transfers and pledges of securities deposited with the Clearing
         Agency.

                 "Company" means Atlas Air, Inc., a Delaware corporation, or
         its successor in interest pursuant to Section 5.02, or (only in the
         context of provisions hereof, if any, when such reference is required
         for purposes of compliance with the Trust Indenture Act) any other
         "obligor" (within the meaning of the Trust Indenture Act) with respect
         to the Certificates.

                 "Controlling Party" means the Person entitled to act as such
         pursuant to the terms of the Intercreditor Agreement.

                 "Corporate Trust Office" means, with respect to the Trustee or
         any Loan Trustee, the office of such trustee in the city at which at
         any particular time its corporate trust business shall be principally
         administered.
<PAGE>   11
                                       5

                 "Delivery Period Termination Date" has the meaning specified
         in the Related Pass Through Trust Agreement.

                 "Direction" has the meaning specified in Section 1.04(a).

                 "Equipment Notes" means all of the equipment notes issued
         under the Indentures.

                 "ERISA" means the Employee Retirement Income Security Act of
         1974, as amended from time to time, or any successor federal statute.

                 "Escrow Account" has the meaning specified in Section 2.02(b).

                 "Escrow Agent" means, initially, First Security, National
         Association, and any replacement or successor therefor appointed in
         accordance with the Escrow Agreement.

                 "Escrow Agreement" means the Escrow and Paying Agent Agreement
         dated as of February 9, 1998 relating to the Certificates, among the
         Escrow Agent, the Escrow Paying Agent, the Related Trustee (and after
         the Transfer Date, the Trustee) and Placement Agents, as the same may
         be amended, supplemented or otherwise modified from time to time in
         accordance with its terms.

                 "Escrow Paying Agent" means the Person acting as paying agent
         under the Escrow Agreement.

                 "Escrow Receipt" means the receipt substantially in the form
         annexed to the Escrow Agreement representing a fractional undivided
         interest in the funds held in escrow thereunder.

                 "Escrowed Funds" has the meaning specified in Section 2.02(b).

                 "Event of Default" means an Indenture Event of Default under
         any Indenture pursuant to which Equipment Notes held by such Trust
         were issued.

                 "Exchange Certificates" means the certificates substantially
         in the form of Exhibit A to the Related Pass Through Trust Agreement
         issued in exchange for the Certificates pursuant to the Registration
         Rights Agreement and authenticated hereunder.

                 "Fractional Undivided Interest" means the fractional undivided
         interest in a Trust that is evidenced by a Certificate.
<PAGE>   12
                                       6


                 "Global Certificates" has the meaning specified in Section
         3.01(d).

                 "Indenture" means each of the separate trust indentures and
         mortgages relating to the Aircraft, each as specified or described in
         a Delivery Notice delivered pursuant to the Note Purchase Agreement or
         the related Participation Agreement, in each case as the same may be
         amended, supplemented or otherwise modified from time to time in
         accordance with its terms.

                 "Indenture Event of Default" means, with respect to any
         Indenture, any Indenture Event of Default (as such term is defined in
         such Indenture).

                 "Initial Regular Distribution Date" means, with respect to the
         Certificates, the first Regular Distribution Date on which a Scheduled
         Payment is to be made.

                 "Institutional Accredited Investor" means an institutional
         investor that is an "accredited investor" within the meaning set forth
         in Rule 501(a)(1), (2), (3) or (7) of Regulation D under the
         Securities Act.

                 "Intercreditor Agreement" means the Intercreditor Agreement
         dated as of February 9, 1998 among the Related Trustee (and after the
         Transfer Date, the Trustee), the Related Other Trustees (and after the
         Transfer Date, the Other Trustees), the Liquidity Providers, the
         liquidity providers relating to the Certificates issued under (and as
         defined in) each of the Related Other Pass Through Trust Agreements,
         and Wilmington Trust Company, as Subordination Agent and as trustee
         thereunder, as amended, supplemented or otherwise modified from time
         to time in accordance with its terms.

                 "Issuance Date" means, with respect to the Certificates, the
         date of the issuance of such Certificates.

                 "Investors" means the Placement Agents together with all
         subsequent beneficial owners of the Certificates.

                 "Lease" means, with respect to each Leased Aircraft, any lease
         between an Owner Trustee, as the lessor, and the Company, as the
         lessee, referred to in the related Indenture, as such lease may be
         amended, supplemented or otherwise modified in accordance with its
         terms; and "Leases" means all such Leases.

                 "Leased Aircraft" has the meaning specified in the recitals
         hereto.
<PAGE>   13
                                       7

                 "Leased Aircraft Participation Agreement" means any
         participation agreement substantially in the form of Exhibit A-1 to
         the Note Purchase Agreement, as the same may be amended, supplemented
         or otherwise modified in accordance with its terms.

                 "Letter of Representations" means, with respect to the
         Certificates, an agreement among the Company, the Related Trustee (and
         after the Transfer Date, the Trustee) and the initial Clearing Agency.

                 "Liquidity Facility" means, with respect to the Certificates,
         any revolving credit agreement, letter of credit or similar facility
         relating to the Certificates between a bank or other financial
         institution and a Subordination Agent, as amended, replaced,
         supplemented or otherwise modified from time to time in accordance
         with its terms and the terms of any Intercreditor Agreement.

                 "Liquidity Provider" means, with respect to the Certificates,
         a bank or other financial institution that agrees to provide a
         Liquidity Facility for the benefit of the holders of Certificates.

                 "Loan Trustee" means, with respect to any Equipment Note or
         the Indenture applicable thereto, the bank or trust company designated
         as loan or indenture trustee under such Indenture, and any successor
         to such Loan Trustee as such trustee; and "Loan Trustees" means all of
         the Loan Trustees under the Indentures.

                 "Non-U.S. Person" means a Person that is not a "U.S. person",
         as defined in Regulation S.

                 "Note Documents" means, with respect to the Certificates, the
         Equipment Notes with respect to such Certificates and, with respect to
         such Equipment Notes, the related Indenture, Note Purchase Agreement
         and, if the related Aircraft is leased to the Company, the related
         Lease and the related Owner Trustee's Purchase Agreement.

                 "Note Purchase Agreement" means, with respect to the
         Certificates, any note purchase, refunding, participation or similar
         agreement; and "Note Purchase Agreements" means all such agreements.

                 "Offering Memorandum" means the Offering Memorandum dated
         January 27, 1998 relating to the offering of the Certificates and the
         certificates offered under the  Related Other Pass Through Trust
         Agreements.

                 "Officer's Certificate" means a certificate signed, (a) in the
         case of the Company, by the Chairman or Vice Chairman of the Board of
         Directors, the
<PAGE>   14
                                       8

         President, any Vice President or the Treasurer of the Company, signing
         alone, or (b) in the case of the Trustee or an Owner Trustee or a Loan
         Trustee, a Responsible Officer of the Trustee or such Owner Trustee or
         such Loan Trustee, as the case may be.

                 "Offshore Certificates Exchange Date" has the meaning
         specified in Section 3.01(d).

                 "Offshore Global Certificates" has the meaning specified in
         Section 3.01(d).

                 "Offshore Physical Certificates" has the meaning specified in
         Section 3.01(e).

                 "Opinion of Counsel" means a written opinion of legal counsel
         who (a) in the case of counsel for the Company may be (i) a senior
         attorney of the Company one of whose principal duties is furnishing
         advice as to legal matters, (ii) Cahill Gordon & Reindel or (iii) such
         other counsel designated by the Company and reasonably acceptable to
         the Trustee and (b) in the case of any Owner Trustee or any Loan
         Trustee, may be such counsel as may be designated by any of them
         whether or not such counsel is an employee of any of them, and who
         shall be reasonably acceptable to the Trustee.

                 "Other Pass Through Trust Agreements" means each of the two
         other Atlas Air 1998-1 Pass Through Trust Agreements relating to Atlas
         Air Pass Through Trust, Series 1998-1B-S and Atlas Air Pass Through
         Trust, Series 1998-1C-S, dated the date hereof.

                 "Other Trustees" means the trustees under the Other Pass
         Through Trust Agreements, and any successor or other trustee appointed
         as provided therein.

                 "Other Trusts" means the Atlas Air Pass Through Trust
         1998-1B-S and the Atlas Air Pass Through Trust 1998-1C-S, each created
         on the date hereof.

                 "Outstanding" when used with respect to Certificates, means,
         as of the date of determination, all Certificates theretofore
         authenticated and delivered under this Agreement, except:

                          (a)     Certificates theretofore cancelled by the
                 Registrar or delivered to the Trustee or the Registrar for
                 cancellation;

                          (b)     All of the Certificates if money in the full
                 amount required to make the final distribution with respect to
                 such series pursuant to Section 11.01 hereof has been
                 theretofore deposited with the Trustee in trust
<PAGE>   15
                                       9

                 for the Holders of the Certificates as provided in Section
                 4.01 pending distribution of such money to such
                 Certificateholders pursuant to payment of such final
                 distribution payment; and

                          (c)     Certificates in exchange for or in lieu of
                 which other Certificates have been authenticated and delivered
                 pursuant to this Agreement.

                 "Owned Aircraft" has the meaning specified in the recitals
         hereto.

                 "Owned Aircraft Participation Agreement" means any
         participation agreement substantially in the form of Exhibit C-1 to
         the Note Purchase Agreement, as the same may be amended, supplemented
         or otherwise modified in accordance with its terms.

                 "Owner Trustee's Purchase Agreement" has the meaning, with
         respect to the Certificates if the related Aircraft is leased to the
         Company, specified therefor in the related Lease.

                 "Participation Agreement" means, collectively, the Leased
         Aircraft Participation Agreement and the Owned Aircraft Participation
         Agreement.

                 "Paying Agent" means, with respect to the Certificates, the
         paying agent maintained and appointed for the Certificates pursuant to
         Section 7.12.

                 "Permanent Offshore Global Certificates" has the meaning
         specified in Section 3.01(d).

                 "Permitted Investments" means obligations of the United States
         of America or agencies or instrumentalities thereof for the payment of
         which the full faith and credit of the United States of America is
         pledged, maturing in not more than 60 days after the date of
         acquisition thereof or such lesser time as is required for the
         distribution of any Special Payments on a Special Distribution Date.

                 "Person" means any person, including any individual,
         corporation, limited liability company, partnership, joint venture,
         association, joint-stock company, trust, trustee, unincorporated
         organization, or government or any agency or political subdivision
         thereof.

                 "Physical Certificates" has the meaning specified in Section
         3.01.

                 "Placement Agents" means Morgan Stanley & Co. Incorporated, BT
         Alex. Brown Incorporated, Donaldson, Lufkin & Jenrette Securities
         Corporation and Goldman, Sachs & Co.
<PAGE>   16
                                       10


                 "Placement Agreement" means the Placement Agreement dated
         January 27, 1998 among the Placement Agents and the Company, as the
         same may be amended, supplemented or otherwise modified from time to
         time in accordance with its terms.

                 "Pool Balance" means, as of any date, (i) the original
         aggregate face amount of the Certificates as defined in the Related
         Pass Through Trust Agreement less (ii) the aggregate amount of all
         payments made in respect of the Certificates other than payments made
         in respect of interest or premium thereon or reimbursement of any
         costs or expenses incurred in connection therewith.  The Pool Balance
         as of any Distribution Date shall be computed after giving effect to
         the payment of principal, if any, on the Equipment Notes or other
         Trust Property held in the Trust and the distribution thereof to be
         made on such Distribution Date.

                 "Pool Factor" means, as of any date, the quotient (rounded to
         the seventh decimal place) computed by dividing (i) the Pool Balance
         of such series as at such date by (ii) the original aggregate face
         amount of the Certificates as defined in the Related Pass Through
         Trust Agreement.  The Pool Factor as of any Distribution Date shall be
         computed after giving effect to the payment of principal, if any, on
         the Equipment Notes or other Trust Property held in the Trust and the
         distribution thereof to be made on such Distribution Date.

                 "Potential Purchaser" has the meaning, with respect to any
         Certificateholder, specified in Section 6.01(b).

                 "Private Placement Legend" has the meaning specified in
         Section 3.02(a).

                 "PTC Event of Default" means, with respect to the
         Certificates, any failure to pay within ten Business Days of the due
         date thereof:  (i) the outstanding Pool Balance of such series of
         Certificates on the date specified in any Trust Supplement for such
         payment or (ii) interest due on the Certificates on any Distribution
         Date (unless the related Subordination Agent shall have made an
         Interest Drawing or Drawings (as defined in the related Intercreditor
         Agreement), or a withdrawal or withdrawals pursuant to a cash
         collateral account under such Intercreditor Agreement, with respect
         thereto in an aggregate amount sufficient to pay such interest and
         shall have distributed such amount to the Trustee).

                 "Purchasing Certificateholder" has the meaning, with respect
         to any Certificateholder, specified in Section 6.01(b).

                 "QIB" means a qualified institutional buyer as defined in Rule
         144A.
<PAGE>   17
                                       11

                 "Record Date" means, with respect to any Trust or the related
         series of Certificates, (i) for Scheduled Payments to be distributed
         on any Regular Distribution Date, other than the final distribution
         with respect to such series, the 15th day (whether or not a Business
         Day) preceding such Regular Distribution Date, and (ii) for Special
         Payments to be distributed on any Special Distribution Date, other
         than the final distribution with respect to such series, the 15th day
         (whether or not a Business Day) preceding such Special Distribution
         Date.

                 "Register" and "Registrar" means, each with respect to the
         Certificates, the register maintained and the registrar appointed
         pursuant to Sections 3.04 and 7.12.

                 "Registration Event" has the meaning set forth in the
         Placement Agreement.

                 "Registration Rights Agreement" means the Registration Rights
         Agreement dated February 9, 1998, among the Placement Agents, the
         Related Trustee (and after the Transfer Date, the Trustee), the
         Related Other Trustees (and after the Transfer Date, the Other
         Trustees) and the Company, as amended, supplemented or otherwise
         modified from time to time in accordance with its terms.

                 "Registration Statement" means the Registration Statement
         defined in the Registration Rights Agreement.

                 "Regular Distribution Date" means, with respect to
         distributions of Scheduled Payments in respect of any series of
         Certificates, each date designated as such in this Agreement, until
         payment of all the Scheduled Payments to be made under the Equipment
         Notes held in the Trust have been made.

                 "Regulation S" means Regulation S under the Securities Act or
         any successor regulation thereto.

                 "Related Pass Through Trust Agreement" means the Atlas Air
         1998-1A-0 Pass Through Trust Agreement relating to the Atlas Air Pass
         Through Trust 1998-1A-0 and entered into by the Company and the
         Related Trustee, as amended, supplemented or otherwise modified from
         time to time in accordance with its terms.

                 "Related Trust" means the Atlas Pass Through Trust 1998-1A-O,
         formed under the Related Pass Through Trust Agreement.

                 "Related Trustee" means the trustee under the Related Pass
         Through Trust Agreement.
<PAGE>   18
                                       12

                 "Request" means a request by the Company setting forth the
         subject matter of the request accompanied by an Officer's Certificate
         and an Opinion of Counsel as provided in Section 1.02 of this
         Agreement.

                 "Responsible Officer" means, with respect to any Trustee, any
         Loan Trustee and any Owner Trustee, any officer in the Corporate Trust
         Department of the Trustee, Loan Trustee or Owner Trustee or any other
         officer customarily performing functions similar to those performed by
         the persons who at the time shall be such officers, respectively, or
         to whom any corporate trust matter is referred because of his
         knowledge of and familiarity with a particular subject.

                 "Responsible Party" means, with respect to the Certificates,
         the person designated as such in the related Trust Supplement.

                 "Rule 144A" means Rule 144A under the Securities Act and any
         successor rule thereto.

                 "Scheduled Payment" means, with respect to any Equipment Note,
         (i) any payment of principal or interest on such Equipment Note (other
         than any such payment which is not in fact received by the Trustee or
         any Subordination Agent within five days of the date on which such
         payment is scheduled to be made) or (ii) any payment of interest on
         the Certificates with funds drawn under the Liquidity Facility for
         such series, which payment represents the installment of principal on
         such Equipment Note at the stated maturity of such installment, the
         payment of regularly scheduled interest accrued on the unpaid
         principal amount of such Equipment Note, or both; provided, however,
         that any payment of principal, premium, if any, or interest resulting
         from the redemption or purchase of any Equipment Note shall not
         constitute a Scheduled Payment.

                 "SEC" means the Securities and Exchange Commission, as from
         time to time constituted or created under the Securities Exchange Act
         of 1934, as amended, or, if at any time after the execution of this
         instrument such Commission is not existing and performing the duties
         now assigned to it under the Trust Indenture Act, then the body
         performing such duties on such date.

                 "Selling Certificateholder" has the meaning, with respect to
         any Certificateholder, specified in Section 6.01(b).

                 "Shelf Registration Statement" has the meaning set forth in
         the Registration Rights Agreement.
<PAGE>   19
                                       13

                 "Special Distribution Date" means, with respect to the
         Certificates, each date on which a Special Payment is to be
         distributed as specified in this Agreement.

                 "Special Payment" means (i) any payment (other than a
         Scheduled Payment) in respect of, or any proceeds of, any Equipment
         Note or Trust Indenture Estate (as defined in each Indenture) or
         Special Redemption Premium, (ii) the amounts required to be
         distributed pursuant to the last paragraph of Section 2.02(b) or (iii)
         the amounts required to be distributed pursuant to the penultimate
         paragraph of Section 2.02(b).

                 "Special Payments Account" means, with respect to the
         Certificates, the account or accounts created and maintained for such
         series pursuant to Section 4.01(b) and the related Trust Supplement.

                 "Special Redemption Premium" means the premium payable by the
         Company in respect of the Final Withdrawal pursuant to the Note
         Purchase Agreement.

                 "Specified Investments" means, with respect to any Trust, (i)
         obligations of, or guaranteed by, the United States Government or
         agencies thereof, (ii) open market commercial paper of any corporation
         incorporated under the laws of the United States of America or any
         state thereof rated at least P-2 or its equivalent by Moody's
         Investors Service, Inc. or at least A-2 or its equivalent by Standard
         & Poor's Ratings Services, a division of The McGraw-Hill Companies,
         Inc., (iii) certificates of deposit issued by commercial banks
         organized under the laws of the United States or of any political
         subdivision thereof having a combined capital and surplus in excess of
         $100,000,000 which banks or their holding companies have a rating of A
         or its equivalent by Moody's Investors Service, Inc. or Standard &
         Poor's Ratings Services, a division of The McGraw-Hill Companies,
         Inc.; provided, however, that the aggregate amount at any one time so
         invested in certificates of deposit issued by any one bank shall not
         exceed 5% of such bank's capital and surplus, (iv) U.S. dollar-
         denominated offshore certificates of deposit issued by, or offshore
         time deposits with, any commercial bank described in clause (iii)
         above or any subsidiary thereof and (v) repurchase agreements with any
         financial institution having combined capital and surplus of at least
         $100,000,000 with any of the obligations described in clauses (i)
         through (iv) above as collateral; provided further that if all of the
         above investments are unavailable, the entire amounts to be invested
         may be used to purchase federal funds from an entity described in
         clause (iii) above.

                 "Subordination Agent" has the meaning specified therefor in
         the Intercreditor Agreement.

                 "Substitute Aircraft" has the meaning specified in the Note
         Purchase Agreement.
<PAGE>   20
                                       14


                 "Temporary Offshore Global Certificates" has the meaning
         specified in Section 3.01(d).

                 "Transfer Date" has the meaning specified in Section 11.01.

                 "Triggering Event" has the meaning specified therefor in the
         Intercreditor Agreement.

                 "Trust" means the trust under this Agreement.

                 "Trustee" means Wilmington Trust Company, or its successor in
         interest, and any successor or other trustee appointed as provided
         herein.

                 "Trustee's Liens" has the meaning specified in Section 7.17.

                 "Trust Indenture Act", except as otherwise provided in Section
         9.06, means, with respect to any particular Trust, the United States
         Trust Indenture Act of 1939, as in force at the date as of which the
         related Pass Through Trust Agreement was executed.

                 "Trust Property" means (i) subject to the Intercreditor
         Agreement, the Equipment Notes held as the property of the Trust, all
         monies at any time paid thereon and all monies due and to become due
         thereunder, (ii) funds from time to time deposited in the Escrow
         Account, the Certificate Account and the Special Payments Account and,
         subject to the Intercreditor Agreement, any proceeds from the sale by
         the Trustee pursuant to Article VI hereof of any such Equipment Note,
         (iii) all rights of the Trust and the Trustee, on behalf of the Trust,
         under the Intercreditor Agreement, the Escrow Agreement, the Note
         Purchase Agreement and the Liquidity Facilities, including, without
         limitation, all rights to receive certain payments thereunder, and all
         monies paid to the Trustee on behalf of the Trust pursuant to the
         Intercreditor Agreement or the Liquidity Facilities, provided that
         rights with respect to the Deposits or under the Escrow Agreement,
         will not constitute Trust Property.

                 "U.S. Global Certificate" has the meaning specified in Section
         3.01(c).

                 "U.S. Physical Certificates" has the meaning specified in
         Section 3.01(e).

                 "7.38% 1998-1A Initial Pass Through Certificates" has the
         meaning specified in Section 3.01(a).

                 "7.38% 1998-1A Exchange Pass Through Certificates" has the
         meaning specified in Section 3.01(a).
<PAGE>   21
                                       15


                 Section 1.02.  Compliance Certificates and Opinions.  Upon any
application or request by the Company, any Owner Trustee or any Loan Trustee to
the Trustee to take any action under any provision of this Agreement, the
Company, such Owner Trustee or such Loan Trustee, as the case may be, shall
furnish to the Trustee (i) an Officer's Certificate stating that, in the
opinion of the signers, all conditions precedent, if any, provided for in this
Agreement relating to the proposed action have been complied with and (ii) an
Opinion of Counsel stating that in the opinion of such counsel all such
conditions precedent, if any, have been complied with, except that in the case
of any such application or request as to which the furnishing of such documents
is specifically required by any provision of this Agreement relating to such
particular application or request, no additional certificate or opinion need be
furnished.

                 Every certificate or opinion with respect to compliance with a
condition or covenant provided for in this Agreement (other than a certificate
provided pursuant to Section 8.04(d)) shall include:

                 (a)      a statement that each individual signing such
         certificate or opinion has read such covenant or condition and the
         definitions in this Agreement relating thereto;

                 (b)      a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate or opinion are based;

                 (c)      a statement that, in the opinion of each such
         individual, he has made such examination or investigation as is
         necessary to enable him to express an informed opinion as to whether
         or not such covenant or condition has been complied with; and

                 (d)      a statement as to whether, in the opinion of each
         such individual, such condition or covenant has been complied with.

                 Section 1.03.  Form of Documents Delivered to Trustee.  In any
case where several matters are required to be certified by, or covered by an
opinion of, any specified Person, it is not necessary that all such matters be
certified by, or covered by the opinion of, only one such Person, or that they
be so certified or covered by only one document, but one such Person may
certify or give an opinion with respect to some matters and one or more other
such Persons as to other matters and any such Person may certify or give an
opinion as to such matters in one or several documents.

                 Where any Person is required to make, give or execute two or
more applications, requests, consents, certificates, statements, opinions or
other instruments under this Agreement, they may, but need not, be consolidated
and form one instrument.
<PAGE>   22
                                       16


                 Section 1.04.  Directions of Certificateholders.  (a)  Any
direction, consent, request, demand, authorization, notice, waiver or other
action provided by this Agreement in respect of the Certificates to be given or
taken by Certificateholders (a "Direction") may be embodied in and evidenced by
one or more instruments of substantially similar tenor signed by such
Certificateholders in person or by an agent or proxy duly appointed in writing;
and, except as herein otherwise expressly provided, such action shall become
effective when such instrument or instruments are delivered to the Trustee and,
when it is hereby expressly required pursuant to this Agreement, to the Company
or any Loan Trustee.  Such instrument or instruments (and the action embodied
therein and evidenced thereby) are herein sometimes referred to as the "Act" of
the Certificateholders signing such instrument or instruments.  Proof of
execution of any such instrument or of a writing appointing any such agent or
proxy shall be sufficient for any purpose of this Trust Agreement and
conclusive in favor of the Trustee, the Company and the related Loan Trustee,
if made in the manner provided in this Section 1.04.

                 (b)      The fact and date of the execution by any Person of
any such instrument or writing may be proved by the certificate of any notary
public or other officer of any jurisdiction authorized to take acknowledgments
of deeds or administer oaths that the Person executing such instrument
acknowledged to him the execution thereof, or by an affidavit of a witness to
such execution sworn to before any such notary or such other officer, and where
such execution is by an officer of a corporation or association or a member of
a partnership, on behalf of such corporation, association or partnership, such
certificate or affidavit shall also constitute sufficient proof of his
authority.  The fact and date of the execution of any such instrument or
writing, or the authority of the Person executing the same, may also be proved
in any other reasonable manner which the Trustee deems sufficient.

                 (c)      In determining whether the Certificateholders of the
requisite Fractional Undivided Interests of Certificates Outstanding have given
any Direction under this Agreement, Certificates owned by the Company or any
Affiliate thereof shall be disregarded and deemed not to be Outstanding for
purposes of any such determination.  In determining whether the Trustee shall
be protected in relying upon any such Direction, only Certificates which the
Trustee knows to be so owned shall be so disregarded.  Notwithstanding the
foregoing, (i) if any such Person owns 100% of the Certificates Outstanding,
such Certificates shall not be so disregarded, and (ii) if any amount of
Certificates so owned by any such Person have been pledged in good faith, such
Certificates shall not be disregarded if the pledgee establishes to the
satisfaction of the Trustee the pledgee's right so to act with respect to such
Certificates and that the pledgee is not the Company or any Affiliate thereof.

                 (d)      The Company may, at its option, by delivery of an
Officer's Certificate to the Trustee, set a record date to determine the
Certificateholders in respect of the Certificates, entitled to give any
Direction.  Notwithstanding Section 316(c) of the Trust
<PAGE>   23
                                       17

Indenture Act, such record date shall be the record date specified in such
Officer's Certificate, which shall be a date not more than 30 days prior to the
first solicitation of Certificateholders of the applicable series in connection
therewith.  If such a record date is fixed, such Direction may be given before
or after such record date, but only the Certificateholders of record of the
applicable series at the close of business on such record date shall be deemed
to be Certificateholders for the purposes of determining whether
Certificateholders of the requisite proportion of Outstanding Certificates have
authorized or agreed or consented to such Direction, and for that purpose the
Outstanding Certificates shall be computed as of such record date; provided,
however, that no such Direction by the Certificateholders on such record date
shall be deemed effective unless it shall become effective pursuant to the
provisions of this Agreement not later than one year after such record date.

                 (e)      Any Direction by the Holder of any Certificate shall
bind the Holder of every Certificate issued upon the transfer thereof or in
exchange therefor or in lieu thereof, whether or not notation of such Direction
is made upon such Certificate.

                 (f)      Except as otherwise provided in Section 1.04(c),
Certificates owned by or pledged to any Person shall have an equal and
proportionate benefit under the provisions of this Agreement, without
preference, priority or distinction as among all of the Certificates.


                                   ARTICLE II

                       ACQUISITION OF THE TRUST PROPERTY

                 Section 2.01.    Acquisition of Trust Property.  The Trustee
is hereby irrevocably authorized and directed to execute and deliver the
Assignment and Assumption Agreement on the date specified in Section 11.01 of
the Related Pass Through Trust Agreement, subject only to the satisfaction of
the conditions set forth in said Section 11.01.  This Agreement (except only
for the immediately preceding sentence hereof, which is effective upon
execution and delivery hereof) shall become effective upon the execution and
delivery of the Assignment and Assumption Agreement by the Trustee and the
Related Trustee, automatically and without any further signature or action on
the part of the Company and the Trustee, and shall thereupon constitute the
legal, valid and binding obligation of the parties hereto enforceable against
each of the parties hereto in accordance with its terms.  Upon such execution
and delivery of the Assignment and Assumption Agreement, the Related Trust
shall be terminated, the Certificateholders shall receive beneficial interests
in the Trust in exchange for their interests in the Related Trust equal to
their respective beneficial interests in the Related Trust and the
"Outstanding" (as defined in the Related Pass Through Trust Agreement) pass
through certificates representing fractional undivided interests in the Related
Trust shall be deemed for all purposes of this Agreement,
<PAGE>   24
                                       18

without further signature or action of any party or Certificateholder, to be
Certificates representing the same Fractional Undivided Interests in the Trust
and Trust Property.  By acceptance of its Certificate, each Certificateholder
consents to and ratifies such assignment, transfer and delivery of the trust
property of the Related Trust to the Trustee upon the execution and delivery of
the Assignment and Assumption Agreement.

                 Section 2.02. [Intentionally omitted]

                 Section 2.03.  Acceptance by Trustee.  The Trustee, upon the
execution and delivery of the Assignment and Assumption Agreement, acknowledges
its acceptance of all right, title and interest in and to the Trust Property
and will hold such right, title and interest for the benefit of all then
present and future Certificateholders, upon the trusts herein set forth.  By
its payment for and acceptance of each Certificate issued under the Related
Pass Through Trust Agreement and deemed issued under this Agreement, each
Holder of such Certificate as grantor of such Trust thereby joins in the
creation and declaration of such Trust.

                 Section 2.04.  Limitation of Powers.  The Trust is constituted
solely for the purpose of making the investment in the Equipment Notes, and,
except as set forth herein, the Trustee shall not be authorized or empowered to
acquire any other investments or engage in any other activities and, in
particular, the Trustee shall not be authorized or empowered to do anything
that would cause such Trust to fail to qualify as a "grantor trust" for federal
income tax purposes (including, as subject to this restriction, acquiring any
Aircraft (as defined in the respective Indentures) by bidding such Equipment
Notes or otherwise, or taking any action with respect to any such Aircraft once
acquired).


                                  ARTICLE III

                                THE CERTIFICATES

                 Section 3.01.  Title, Form, Denomination and Execution of
Certificates.  (a)  The Initial Certificates shall be known as the "7.38%
1998-1A-S Initial Pass Through Certificates" and the Exchange Certificates
shall be known as the "7.38% 1998-1A-S Exchange Pass Through Certificates", in
each case, of the Trust.  Each Certificate will represent a fractional
undivided interest in the Trust and shall be substantially in the form set
forth as Exhibit A to the Related Pass Through Trust Agreement, with such
appropriate insertions, omissions, substitutions and other variations as are
required or permitted by the Related Pass Through Trust Agreement or by this
Agreement, as the case may be, or as the Trustee may deem appropriate, to
reflect the fact that the Certificates are being issued hereunder as opposed to
under the Related Pass Through Trust Agreement and may have such letters,
numbers or other marks of identification and such legends or endorsements
<PAGE>   25
                                       19

placed thereon as may be required to comply with the rules of any securities
exchange or as may, consistently herewith, be determined by the officers
executing such Certificates, as evidenced by their execution of the
Certificates.  Any portion of the text of any Certificate may be set forth on
the reverse thereof, with an appropriate reference thereto on the face of the
Certificate.

                 (b)      The Initial Certificates shall be issued only in
fully registered form without coupons and only in denominations of $100,000 or
integral multiples of $1,000 in excess thereof, except that one Certificate may
be issued in a denomination of less than $100,000.  The Exchange Certificates
will be issued in denominations of $1,000 or integral multiples thereof.  Each
Certificate shall be dated the date of its authentication.  The aggregate
Fractional Undivided Interest of Certificates initially deemed issued hereunder
shall not at any time exceed the aggregate principal amount of "Outstanding"
pass through trust certificates representing fractional undivided interests in
the Related Trust on the Transfer Date.

                 (c)      Initial Certificates offered and sold in reliance on
Rule 144A shall be issued initially in the form of a single permanent global
Certificate in registered form, substantially in the form set forth as Exhibit
A to the Related Pass Through Trust Agreement (the "U.S. Global Certificate"),
duly executed and authenticated by the Trustee as hereinafter provided.  The
U.S. Global Certificate will be registered in the name of a nominee for the
Depositary and deposited with the Trustee, as custodian for the Depositary.
The aggregate principal amount of the U.S. Global Certificate may from time to
time be increased or decreased by adjustments made on the records of the
Depositary or its nominee, or of the Trustee, as custodian for the Depositary
or its nominee, as hereinafter provided.

                 (d)      Initial Certificates offered and sold in offshore
transactions in reliance on Regulation S shall be issued initially in the form
of a single temporary global Certificate in registered form, substantially in
the form set forth as Exhibit A to the Related Pass Through Trust Agreement
(the "Temporary Offshore Global Certificate") duly executed and authenticated
by the Trustee as hereinafter provided.  The Temporary Offshore Global
Certificates will be registered in the name of a nominee of the Depositary for
credit to the account of the Agent Members acting as depositaries for Euroclear
and Cedel and deposited with the Trustee as custodian for the Depositary.  At
any time following March 21, 1998 (the "Offshore Certificates Exchange Date"),
upon receipt by the Trustee of a certificate substantially in the form of
Exhibit B to the Related Pass Through Trust Agreement, a single permanent
global Certificate in registered form substantially in the form set forth in
Exhibit A (the "Permanent Offshore Global Certificate"; and together with the
Temporary Offshore Global Certificate, the "Offshore Global Certificates"),
duly executed and authenticated by the Trustee as hereinafter provided, shall
be registered in the name of a nominee for the Depositary and deposited with
the Trustee, as custodian for the Depositary, and the Registrar shall reflect
on its books and records the date of such transfer and a decrease in the
principal
<PAGE>   26
                                       20

amount of any Temporary Offshore Global Certificate in an amount equal to the
principal amount of the beneficial interest in such Temporary Offshore Global
Certificate transferred.  The U.S. Global Certificate and the Offshore Global
Certificates are sometimes referred to as the "Global Certificates".

                 (e)      Initial Certificates offered and sold to
Institutional Accredited Investors shall be issued in the form of permanent
certificated Certificates in registered form in substantially the form set
forth as Exhibit A to the Related Pass Through Trust Agreement (the "U.S.
Physical Certificates").  Certificates issued pursuant to Section 3.05(b) in
exchange for interests in any Offshore Global Certificate shall be in the form
of permanent certificated Certificates in registered form substantially in the
form set forth in Exhibit A (the "Offshore Physical Certificates").  The
Offshore Physical Certificates and U.S. Physical Certificates are sometimes
collectively herein referred to as the "Physical Certificates".

                 (f)      The Exchange Certificates shall be issued in the form
of one or more global Certificates substantially in the form of Exhibit A to
the Related Pass Through Trust Agreement (each, a "Global Exchange
Certificate"), except that (i) the Private Placement Legend (hereinafter
defined) shall be omitted and (ii)  such Exchange Certificates shall contain
such appropriate insertions, omissions, substitutions and other variations from
the form set forth in Exhibit A to the Related Pass Through Trust Agreement
relating to the nature of the Exchange Certificates as the Responsible Officer
of the Trustee executing such Exchange Certificates on behalf of the Trust may
determine, as evidenced by such officer's execution on behalf of the Trust of
such Exchange Certificates.  Such Global Exchange Certificates shall be in
registered form and be registered in the name of DTC and deposited with the
Trustee, at its Corporate Trust Office, as custodian for DTC.  The aggregate
principal amount of any Global Exchange Certificate may from time to time be
increased or decreased by adjustments made on the records of the Trustee, as
custodian for DTC for such Global Exchange Certificate, which adjustments shall
be conclusive as to the aggregate principal amount of any such Global Exchange
Certificate.  Subject to clause (i) and (ii)  of the first sentence of this
Section 3.01(f), the terms hereof applicable to Restricted Global Certificates
and/or Global Certificates shall apply to the Global Exchange Certificates,
mutatis mutandis.

                 (g)      The definitive Certificates shall be in registered
form and shall be typed, printed, lithographed or engraved or produced by any
combination of these methods or may be produced in any other manner, all as
determined by the officers executing such Certificates, as evidenced by their
execution of such Certificates.

                 Section 3.02.  Restrictive Legends.  (a)  Subject to Section
3.06, unless and until (i) an Initial Certificate is sold under an effective
Registration Statement or (ii) an Initial Certificate is exchanged for an
Exchange Certificate pursuant to an effective Exchange Offer Registration
Statement, in each case as provided for in the Registration Rights Agreement,
<PAGE>   27
                                       21

each Global Certificate (other than the Permanent Offshore Global Certificate)
and each U.S. Physical Certificate shall bear the following legend (the
"Private Placement Legend") on the face thereof:

                 THIS CERTIFICATE HAS NOT BEEN REGISTERED UNDER THE U.S.
         SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND
         ACCORDINGLY, MAY NOT BE OFFERED OR SOLD WITHIN THE UNITED STATES OR
         TO, OR FOR THE ACCOUNT OR BENEFIT OF, ANY PERSONS EXCEPT AS SET FORTH
         IN THE FOLLOWING SENTENCE.  BY ITS ACQUISITION HEREOF, THE HOLDER (1)
         REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS
         DEFINED IN RULE 144A UNDER THE SECURITIES ACT), (B) IT IS AN
         INSTITUTIONAL "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1),
         (2), (3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT) (AN
         "INSTITUTIONAL ACCREDITED INVESTOR") OR (C) IT IS NOT A U.S.  PERSON
         AND IS ACQUIRING THIS CERTIFICATE IN AN OFFSHORE TRANSACTION IN
         COMPLIANCE WITH REGULATION S UNDER THE SECURITIES ACT; (2) AGREES THAT
         IT WILL NOT WITHIN TWO YEARS AFTER THE LATER OF THE ORIGINAL ISSUANCE
         OF THIS CERTIFICATE OR THE LAST DATE ON WHICH THIS CERTIFICATE WAS
         HELD BY ATLAS AIR, INC., THE TRUSTEE OR ANY AFFILIATE OF ANY OF SUCH
         PERSONS RESELL OR OTHERWISE TRANSFER THIS CERTIFICATE EXCEPT (A) TO A
         QUALIFIED INSTITUTIONAL BUYER IN COMPLIANCE WITH RULE 144A UNDER THE
         SECURITIES ACT, (B) INSIDE THE UNITED STATES TO AN INSTITUTIONAL
         ACCREDITED INVESTOR ACQUIRING $100,000 OR MORE AGGREGATE PRINCIPAL
         AMOUNT OF  SUCH CERTIFICATE THAT, PRIOR TO SUCH TRANSFER, FURNISHES TO
         THE TRUSTEE A SIGNED LETTER CONTAINING CERTAIN REPRESENTATIONS AND
         AGREEMENTS RELATING TO THE RESTRICTIONS ON TRANSFER OF THIS
         CERTIFICATE (THE FORM OF WHICH LETTER CAN BE OBTAINED FROM THE
         TRUSTEE), (C) OUTSIDE THE UNITED STATES IN AN OFFSHORE TRANSACTION IN
         COMPLIANCE WITH RULE 904 UNDER THE SECURITIES ACT, (D) PURSUANT TO THE
         EXEMPTION FROM REGISTRATION PROVIDED BY RULE 144 UNDER THE SECURITIES
         ACT (IF AVAILABLE) OR (E) PURSUANT TO AN EFFECTIVE REGISTRATION
         STATEMENT UNDER THE SECURITIES ACT; AND (3) AGREES THAT IT WILL
         DELIVER TO EACH PERSON TO WHOM THIS CERTIFICATE IS TRANSFERRED A
         NOTICE SUBSTANTIALLY TO THE EFFECT OF THIS LEGEND.  IN CONNECTION WITH
         ANY TRANSFER OF THIS CERTIFICATE WITHIN TWO YEARS AFTER THE LATER OF
         THE ORIGINAL ISSUANCE OF THIS CERTIFICATE OR THE LAST DATE ON WHICH
         THIS CERTIFICATE WAS HELD BY ATLAS AIR,
<PAGE>   28
                                       22

         INC., THE TRUSTEE OR ANY AFFILIATE OF ANY OF SUCH PERSONS THE HOLDER
         MUST CHECK THE APPROPRIATE BOX SET FORTH ON THE REVERSE HEREOF
         RELATING TO THE MANNER OF SUCH TRANSFER AND SUBMIT THIS CERTIFICATE TO
         THE TRUSTEE.  AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION",
         "UNITED STATES" AND "U.S. PERSON" HAVE THE MEANINGS GIVEN TO THEM BY
         REGULATION S UNDER THE SECURITIES ACT.  THE PASS THROUGH TRUST
         AGREEMENT CONTAINS A PROVISION REQUIRING THE TRUSTEE TO REFUSE TO
         REGISTER ANY TRANSFER OF THIS CERTIFICATE IN VIOLATION OF THE
         FOREGOING RESTRICTIONS.

                 (b)      Each Global Certificate shall also bear the following
legend on the face thereof:

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
         OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO
         THE TRUSTEE OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR
         PAYMENT, AND ANY CERTIFICATE ISSUED IN EXCHANGE FOR THIS CERTIFICATE
         IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
         REQUESTED BY AN AUTHORIZED  REPRESENTATIVE OF DTC (AND ANY PAYMENT
         HEREON IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED
         BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER
         USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
         INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST
         HEREIN.

         TRANSFERS OF THIS GLOBAL CERTIFICATE SHALL BE LIMITED TO TRANSFERS IN
         WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF
         OR SUCH SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL
         CERTIFICATE SHALL BE LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE
         RESTRICTIONS SET FORTH IN SECTIONS 3.05 AND 3.06 OF THE PASS THROUGH
         TRUST AGREEMENT REFERRED TO HEREIN.

                 Section 3.03.  Authentication of Certificates.  (a)
[Intentionally omitted]

                 (b)      No Certificate shall be entitled to any benefit under
this Agreement or be valid or obligatory for any purpose, unless there appears
on such Certificate a certificate of authentication substantially in the form
provided for herein executed by the Related Trustee or by the Trustee by the
manual signature of one of its authorized signatories, and
<PAGE>   29
                                       23

such certificate upon any Certificate shall be conclusive evidence, and the
only evidence, that such Certificate has been duly authenticated and delivered
hereunder.

                 Section 3.04.  Transfer and Exchange.  The Trustee shall cause
to be kept at the office or agency to be maintained by it in accordance with
the provisions of Section 7.12 of this Agreement a register (the "Register")
for the Certificates in which, subject to such reasonable regulations as it may
prescribe, the Trustee shall provide for the registration of the Certificates
and of transfers and exchanges of the Certificates as herein provided.  The
Trustee shall initially be the registrar (the "Registrar") for the purpose of
registering the Certificates and transfers and exchanges of the Certificates as
herein provided.  A Certificateholder may transfer a Certificate by written
application to the Registrar stating the name of the proposed transferee and
otherwise complying with the terms of this Agreement, including providing a
written certificate or other evidence of compliance with any restrictions on
transfer.  No such transfer shall be effected until, and such transferee shall
succeed to the rights of a Certificateholder only upon, final acceptance and
registration of the transfer by the Registrar in the Register.  Prior to the
registration of any transfer by a Certificateholder as provided herein, the
Trustee shall treat the person in whose name the Certificate is registered as
the owner thereof for all purposes, and the Trustee shall not be affected by
notice to the contrary.  Furthermore, the Depositary shall, by acceptance of a
Global Certificate, agree that transfers of beneficial interests in such Global
Certificate may be effected only through a book-entry system maintained by the
Depositary (or its agent), and that ownership of a beneficial interest in the
Certificate shall be required to be reflected in a book entry.  When
Certificates are presented to the Registrar with a request to register the
transfer or to exchange them for an equal face amount of Certificates of other
authorized denominations, the Registrar shall register the transfer or make the
exchange as requested if its requirements for such transactions are met.  To
permit registrations of transfers and exchanges in accordance with the terms,
conditions and restrictions hereof, the Trustee shall execute and authenticate
Certificates at the Registrar's request.  No service charge shall be made for
any registration of transfer or exchange of the Certificates, but the Trustee
may require payment by the transferor of a sum sufficient to cover any transfer
tax or similar governmental charge payable in connection therewith (other than
any such transfer taxes or other similar governmental charges payable upon
exchanges pursuant to Section 3.10 or 9.07).

                 Section 3.05.  Book-Entry Provisions for U.S. Global
Certificate and Offshore Global Certificates.  (a) Members of, or participants
in, the Depositary ("Agent Members") shall have no rights under this Agreement
with respect to any Global Certificate held on their behalf by the Depositary,
or the Trustee as its custodian, and the Depositary may be treated by the
Trustee and any agent of the Trustee as the absolute owner of such Global
Certificate for all purposes whatsoever.  Notwithstanding the foregoing,
nothing herein shall prevent the Trustee or any agent of the Trustee from
giving effect to any written certification, proxy or other authorization
furnished by the Depositary or shall impair, as between the Depositary
<PAGE>   30
                                       24

and its Agent Members, the operation of customary practices governing the
exercise of the rights of a holder of any Certificate.  Upon the issuance of
any Global Certificate, the Registrar or its duly appointed agent shall record
a nominee of the Depositary as the registered holder of such Global
Certificate.

                 (b)      Transfers of any Global Certificate shall be limited
to transfers of such Global Certificate or Offshore Global Certificate in
whole, but not in part, to nominees of the Depositary, its successor or such
successor's nominees.  Beneficial interests in the U.S. Global Certificate and
any Offshore Global Certificate may be transferred in accordance with the rules
and procedures of the Depositary and the provisions of Section 3.06.
Beneficial interests in the U.S. Global Certificate or an Offshore Global
Certificate shall be delivered to all beneficial owners in the form of U.S.
Physical Certificates or Offshore Physical Certificates, as the case may be, if
(i) the Depositary notifies the Trustee that it is unwilling or unable to
continue as Depositary for the U.S. Global Certificate or such Offshore Global
Certificate, as the case may be, and a successor depositary is not appointed by
the Trustee within 90 days of such notice or (ii) an Event of Default has
occurred and is continuing and the Registrar has received a request from the
Depositary to issue Physical Certificates.

                 (c)      Any beneficial interest in one of the Global
Certificates that is transferred to a Person who takes delivery in the form of
an interest in the other Global Certificate will, upon such transfer, cease to
be an interest in such Global Certificate and become an interest in the other
Global Certificate and, accordingly, will thereafter be subject to all transfer
restrictions, if any, and other procedures applicable to beneficial interests
in such other Global Certificate for as long as it remains such an interest.

                 (d)      In connection with the transfer of the entire U.S.
Global Certificate or an entire Offshore Global Certificate to the beneficial
owners thereof pursuant to paragraph (b) of this Section 3.05, such U.S. Global
Certificate or Offshore Global Certificate, as the case may be, shall be deemed
to be surrendered to the Trustee for cancellation, and the Trustee shall
execute, authenticate and deliver, to each beneficial owner identified by the
Depositary in exchange for its beneficial interest in such U.S. Global
Certificate or Offshore Global Certificate, as the case may be, an equal
aggregate principal amount of U.S. Physical Certificates or Offshore Physical
Certificates, as the case may be, of authorized denominations.

                 (e)      Any U.S. Physical Certificate delivered in exchange
for an interest in the U.S. Global Certificate pursuant to paragraph (b) of
this Section 3.05 shall, except as otherwise provided by paragraph (f) of
Section 3.06, bear the Private Placement Legend.

                 (f)      Any Offshore Physical Certificate delivered in
exchange for an interest in an Offshore Global Certificate pursuant to
paragraph (b) of this Section shall, except as
<PAGE>   31
                                       25

otherwise provided by paragraph (f) of Section 3.06, bear the applicable legend
regarding transfer restrictions set forth in Section 3.02(a).

                 (g)      The registered holder of the U.S. Global Certificate
or any Offshore Global Certificate may grant proxies and otherwise authorize
any Person, including Agent Members and Persons that may hold interests through
Agent Members, to take any action which a Holder is entitled to take under this
Agreement or the Certificates.

                 Section 3.06.  Special Transfer Provisions.  Unless and until
(i) an Initial Certificate is sold under an effective Registration Statement,
or (ii) an Initial Certificate is exchanged for an Exchange Certificate
pursuant to an effective Exchange Offer Registration Statement, in each case
pursuant to the Registration Rights Agreement, the following provisions shall
apply to such Initial Certificates:

                 (a)      Transfers to Non-QIB Institutional Accredited
         Investors.  The following provisions shall apply with respect to the
         registration of any proposed transfer of a Certificate to any
         Institutional Accredited Investor which is not a QIB (excluding
         transfers to or by Non-U.S. Persons):

                          (i)     The Registrar shall register the transfer of
                 any Certificate, whether or not such Certificate bears the
                 Private Placement Legend, if (x) the requested transfer is at
                 least three years after the later of the original issue date
                 of the Certificates and the last date on which such
                 Certificate was held by the Company or any affiliate of any
                 such persons or (y) the proposed transferee has delivered to
                 the Registrar a letter substantially in the form of Exhibit D
                 to the Related Pass Through Trust Agreement and the aggregate
                 principal amount of the Certificates being transferred is at
                 least $100,000.

                          (ii)    If the proposed transferor is an Agent Member
                 holding a     beneficial interest in the U.S. Global
                 Certificate, upon receipt by the Registrar of (x) the
                 documents, if any, required by paragraph (i) and (y)
                 instructions given in accordance with the Depositary's and the
                 Registrar's procedures, the Registrar shall reflect on its
                 books and records the date of the transfer and a decrease in
                 the principal amount of such U.S. Global Certificate in an
                 amount equal to the principal amount of the beneficial
                 interest in such U.S. Global Certificate to be transferred,
                 and the Company shall execute, and the Trustee shall
                 authenticate and deliver to the transferor or at its
                 direction, one or more U.S. Physical Certificates of like
                 tenor and amount.

                 (b)      Transfers to QIBs.  The following provisions shall
         apply with respect to the registration of any proposed transfer of an
         Initial Certificate to a QIB (excluding Non-U.S. Persons):
<PAGE>   32
                                       26


                          (i)     If the Certificate to be transferred consists
                 of U.S. Physical  Certificates or an interest in any Temporary
                 Offshore Global Certificate, the Registrar shall register the
                 transfer if such transfer is being made by a proposed
                 transferor who has checked the box provided for on the form of
                 Initial Certificate stating, or has otherwise advised the
                 Trustee and the Registrar in writing, that the sale has been
                 made in compliance with the provisions of Rule 144A to a
                 transferee who has signed the certification provided for on
                 the form of Initial Certificate stating, or has otherwise
                 advised the Trustee and the Registrar in writing, that it is
                 purchasing the Initial Certificate for its own account or an
                 account with respect to which it exercises sole investment
                 discretion and that it, or the Person on whose behalf it is
                 acting with respect to any such account, is a QIB within the
                 meaning of Rule 144A, and is aware that the sale to it is
                 being made in reliance on Rule 144A and acknowledges that it
                 has received such information regarding the Trust and/or the
                 Company as it has requested pursuant to Rule 144A or has
                 determined not to request such information and that it is
                 aware that the transferor is relying upon its foregoing
                 representations in order to claim the exemption from
                 registration provided by Rule 144A.

                          (ii)    Upon receipt by the Registrar of the
                 documents referred to in clause (i) above and instructions
                 given in accordance with the Depositary's and the Registrar's
                 procedures therefor, the Registrar shall reflect on its books
                 and records the date of such transfer and an increase in the
                 principal amount of the U.S. Global Certificate in an amount
                 equal to the principal amount of the U.S.  Physical
                 Certificates or interests in the Temporary Offshore Global
                 Certificate, as the case may be, being transferred, and the
                 Trustee shall cancel such Physical Certificates or decrease
                 the amount of such Temporary Offshore Global Certificate so
                 transferred.

                 (c)      Transfers of Interests in the Permanent Offshore
         Global Certificate or Offshore Physical Certificates.  The Registrar
         shall register any transfer of interests in the Permanent Offshore
         Global Certificate or Offshore Physical Certificates without requiring
         any additional certification.

                 (d)      Transfers to Non-U.S. Persons at Any Time.  The
         following provisions shall apply with respect to any registration of
         any transfer of an Initial Certificate to a Non-U.S. Person:

                          (i)     Prior to the Offshore Certificates Exchange
                 Date, the Registrar shall register any proposed transfer of an
                 Initial Certificate to a Non-U.S. Person upon receipt of a
                 certificate substantially in the form set forth as Exhibit C
                 to the Related Pass Through Trust Agreement from the proposed
                 transferor.
<PAGE>   33
                                       27

                          (ii)    On and after the Offshore Certificates
                 Exchange Date, the Registrar shall register any proposed
                 transfer to any Non-U.S. Person if the Certificate to be
                 transferred is a U.S. Physical Certificate or an interest in
                 the U.S. Global Certificate, upon receipt of a certificate
                 substantially in the form of Exhibit C from the proposed
                 transferor.  The Registrar shall promptly send a copy of such
                 certificate to the Company.

                          (iii)   Upon receipt by the Registrar of (x) the
                 documents, if any, required by paragraph (ii) and (y)
                 instructions in accordance with the Depositary's and the
                 Registrar's procedures, the Registrar shall reflect on its
                 books and records the date of such transfer and a decrease in
                 the principal amount of such U.S. Global Certificate in an
                 amount equal to the principal amount of the beneficial
                 interest in such U.S. Global Certificate to be transferred,
                 and (B) upon receipt by the Registrar of instructions given in
                 accordance with the Depositary's and the Registrar's
                 procedures, the Registrar shall reflect on its books and
                 records the date and an increase in the principal amount of
                 the Offshore Global Certificate in an amount equal to the
                 principal amount of the U.S. Physical Certificate or the U.S.
                 Global Certificate, as the case may be, to be transferred, and
                 the Trustee shall cancel the Physical Certificate, if any, so
                 transferred or decrease the amount of such U.S. Global
                 Certificate.

                 (e)      Private Placement Legend.  Upon the transfer,
         exchange or replacement of Certificates not bearing the Private
         Placement Legend, the Registrar shall deliver Certificates that do not
         bear the Private Placement Legend.  Upon the transfer, exchange or
         replacement of Certificates bearing the Private Placement Legend, the
         Registrar shall deliver only Certificates that bear the Private
         Placement Legend unless either (i) the circumstances contemplated by
         paragraph (a)(i)(x) or (e)(ii) of this Section 3.06 exist or (ii)
         there is delivered to the Registrar an Opinion of Counsel to the
         effect that neither such legend nor the related restrictions on
         transfer are required in order to maintain compliance with the
         provisions of the Securities Act.

                 (f)      General.  By its acceptance of any Certificate
         bearing the Private Placement Legend, each Holder of such a
         Certificate acknowledges the restrictions on transfer of such
         Certificate set forth in this Agreement and agrees that it will
         transfer such Certificate only as provided in this Agreement.  The
         Registrar shall not register a transfer of any Certificate unless such
         transfer complies with the restrictions on transfer of such
         Certificate set forth in this Agreement.  In connection with any
         transfer of Certificates, each Certificateholder agrees by its
         acceptance of the Certificates to furnish the Registrar or the Trustee
         such certifications, legal opinions or other information as either of
         them may reasonably require to confirm that such transfer is being
         made pursuant to an exemption from, or a transaction not subject to,
<PAGE>   34
                                       28

         the registration requirements of the Securities Act; provided that the
         Registrar shall not be required to determine the sufficiency of any
         such certifications, legal opinions or other information.

                 Until such time as no Certificates remain Outstanding, the
Registrar shall retain copies of all letters, notices and other written
communications received pursuant to Section 3.05 or this Section 3.06.  The
Trustee, if not the Registrar at such time, shall have the right to inspect and
make copies of all such letters, notices or other written communications at any
reasonable time upon the giving of reasonable written notice to the Registrar.

                 Section 3.07.  Mutilated, Destroyed, Lost or Stolen
Certificates.  If (a) any mutilated Certificate is surrendered to the Registrar
or the Registrar receives evidence to its satisfaction of the destruction, loss
or theft of any Certificate and (b) there is delivered to the Registrar and the
Trustee such security, indemnity or bond, as may be required by them to save
each of them harmless, then, in the absence of notice to the Registrar or the
Trustee that such destroyed, lost or stolen Certificate has been acquired by a
bona fide purchaser, and provided that the requirements of Section 8-405 of the
Uniform Commercial Code in effect in any applicable jurisdiction are met, the
Trustee shall execute, authenticate and deliver, in exchange for or in lieu of
any such mutilated, destroyed, lost or stolen Certificate, a new Certificate or
Certificates, in authorized denominations and of like Fractional Undivided
Interest and bearing a number not contemporaneously outstanding.

                 In connection with the issuance of any new Certificate under
this Section 3.07, the Trustee may require the payment of a sum sufficient to
cover any tax or other governmental charge that may be imposed in relation
thereto and any other expenses (including the fees and expenses of the Trustee
and the Registrar) connected therewith.

                 Any duplicate Certificate issued pursuant to this Section 3.07
shall constitute conclusive evidence of the appropriate Fractional Undivided
Interest in the Trust, as if originally issued, whether or not the lost, stolen
or destroyed Certificate shall be found at any time.

                 The provisions of this Section are exclusive and shall
preclude (to the extent lawful) all other rights and remedies with respect to
the replacement or payment of mutilated, destroyed, lost or stolen
Certificates.

                 Section 3.08.  Persons Deemed Owners.  Prior to due
presentment of a Certificate for registration of transfer, the Trustee, the
Registrar and any Paying Agent may treat the Person in whose name any
Certificate is registered (as of the day of determination) as the owner of such
Certificate for the purpose of receiving distributions pursuant to Article
<PAGE>   35
                                       29

IV and for all other purposes whatsoever, and none of the Trustee, the
Registrar or any Paying Agent shall be affected by any notice to the contrary.

                 Section 3.09.  Cancellation.  All Certificates surrendered for
payment or transfer or exchange shall, if surrendered to the Trustee or any
agent of the Trustee other than the Registrar, be delivered to the Registrar
for cancellation and shall promptly be cancelled by it.  No Certificates shall
be authenticated in lieu of or in exchange for any Certificates cancelled as
provided in this Section, except as expressly permitted by this Agreement.  All
cancelled Certificates held by the Registrar shall be destroyed and a
certification of their destruction delivered to the Trustee.

                 Section 3.10.  Temporary Certificates.  Until definitive
Certificates are ready for delivery, the Trustee shall authenticate temporary
Certificates.  Temporary Certificates shall be substantially in the form of
definitive Certificates but may have insertions, substitutions, omissions and
other variations determined to be appropriate by the officers executing the
temporary Certificates, as evidenced by their execution of such temporary
Certificates.  If temporary Certificates are issued, the Trustee will cause
definitive Certificates to be prepared without unreasonable delay.  After the
preparation of definitive Certificates, the temporary Certificates shall be
exchangeable for definitive Certificates upon surrender of the temporary
Certificates at the office or agency of the Trustee designated for such purpose
pursuant to Section 7.12, without charge to the Certificateholder.  Upon
surrender for cancellation of any one or more temporary Certificates, the
Trustee shall execute, authenticate and deliver in exchange therefor a like
face amount of definitive Certificates of authorized denominations.  Until so
exchanged, the temporary Certificates shall be entitled to the same benefits
under this Agreement as definitive Certificates.

                 Section 3.11.  Limitation of Liability for Payments.  All
payments and distributions made to Certificateholders shall be made only from
the Trust Property and only to the extent that the Trustee shall have
sufficient income or proceeds from the Trust Property to make such payments in
accordance with the terms of Article IV of this Agreement.  Each
Certificateholder, by its acceptance of a Certificate, agrees that it will look
solely to the income and proceeds from the Trust Property for any payment or
distribution due to such Certificateholder pursuant to the terms of this
Agreement and that it will not have any recourse to the Company, the Trustee,
the Loan Trustees, the Liquidity Providers, the Owner Trustees or the Owner
Participants, except as otherwise expressly provided herein or in the
Intercreditor Agreement.

                 The Company is a party to this Agreement solely for purposes
of meeting the requirements of the Trust Indenture Act, and therefore shall not
have any right, obligation or liability hereunder (except as otherwise
expressly provided herein).
<PAGE>   36
                                       30

                                   ARTICLE IV

                          DISTRIBUTIONS; STATEMENTS TO
                               CERTIFICATEHOLDERS

                 Section 4.01.  Certificate Account and Special Payments
Account.  (a)  The Trustee shall establish and maintain on behalf of the
Certificateholders a Certificate Account as one or more non-interest-bearing
accounts.  The Trustee shall hold such Certificate Account in trust for the
benefit of the Certificateholders, and shall make or permit withdrawals
therefrom only as provided in this Agreement.  On each day when a Scheduled
Payment is made to the Trustee under the Intercreditor Agreement with respect
to the Certificates, the Trustee, upon receipt thereof, shall immediately
deposit the aggregate amount of such Scheduled Payment in such Certificate
Account.

                 (b)      The Trustee shall establish and maintain on behalf of
the Certificateholders a Special Payments Account as one or more accounts,
which shall be non-interest bearing except as provided in Section 4.04. The
Trustee shall hold the Special Payments Account in trust for the benefit of the
Certificateholders and shall make or permit withdrawals therefrom only as
provided in this Agreement.  On each day when one or more Special Payments are
made to the Trustee under the Intercreditor Agreement and upon payment of the
Special Redemption Premium to the Trustee under the Note Purchase Agreement
with respect to the Certificates, the Trustee, upon receipt thereof, shall
immediately deposit the aggregate amount of such Special Payments in such
Special Payments Account.

                 (c)      The Trustee shall present (or, if applicable, cause
the Subordination Agent to present) to the related Loan Trustee of each
Equipment Note such Equipment Note on the date of its stated final maturity or,
in the case of any Equipment Note which is to be redeemed in whole pursuant to
the related Indenture, on the applicable redemption date under such Indenture.

                 Section 4.02.  Distributions from Certificate Account and
Special Payments Account.  (a)  On each Regular Distribution Date with respect
to a series of Certificates or as soon thereafter as the Trustee has confirmed
receipt of the payment of all or any part of the Scheduled Payments due on the
Equipment Notes held (subject to the Intercreditor Agreement) in the related
Trust on such date, the Trustee shall distribute out of the applicable
Certificate Account the entire amount deposited therein pursuant to Section
4.01(a).  There shall be so distributed to each Certificateholder of record of
such series on the Record Date with respect to such Regular Distribution Date
(other than as provided in Section 11.01 concerning the final distribution) by
check mailed to such Certificateholder, at the address appearing in the
Register, such Certificateholder's pro rata share (based on the Fractional
Undivided Interest in the Trust held by such Certificateholder)
<PAGE>   37
                                       31

of the total amount in the applicable Certificate Account, except that, with
respect to Certificates registered on the Record Date in the name of a Clearing
Agency (or its nominee), such distribution shall be made by wire transfer in
immediately available funds to the account designated by such Clearing Agency
(or such nominee).

                 (b)      On each Special Distribution Date with respect to any
Special Payment with respect to the Certificates or as soon thereafter as the
Trustee has confirmed receipt of any Special Payments due on the Equipment
Notes held (subject to the Intercreditor Agreement) in the related Trust or
realized upon the sale of such Equipment Notes or receipt of the Special
Redemption Premium, the Trustee shall distribute out of the applicable Special
Payments Account the entire amount of such applicable Special Payment deposited
therein pursuant to Section 4.01(b).  There shall be so distributed to each
Certificateholder of record of such series on the Record Date with respect to
such Special Distribution Date (other than as provided in Section 11.01
concerning the final distribution) by check mailed to such Certificateholder,
at the address appearing in the Register, such Certificateholder's pro rata
share (based on the Fractional Undivided Interest in the related Trust held by
such Certificateholder) of the total amount in the applicable Special Payments
Account on account of such Special Payment, except that, with respect to
Certificates registered on the Record Date in the name of a Clearing Agency (or
its nominee), such distribution shall be made by wire transfer in immediately
available funds to the account designated by such Clearing Agency (or such
nominee).

                 (c)      The Trustee shall, at the expense of the Company,
cause notice of each Special Payment with respect to a series of Certificates
to be mailed to each Certificateholder at his address as it appears in the
Register.  In the event of redemption or purchase of Equipment Notes held in
the related Trust, such notice shall be mailed not less than 15 days prior to
the Special Distribution Date for the Special Payment resulting from such
redemption or purchase, which Special Distribution Date shall be the date of
such redemption or purchase.  In the event that any Special Redemption Premium
is to be paid by the Company to the Trustee under the Note Purchase Agreement,
such notice shall be mailed, together with the notice by the Escrow Paying
Agent under Section 2.06 of the Escrow Agreement, not less than 20 days prior
to the Special Distribution Date for such amount, which Special Distribution
Date shall be the Final Withdrawal Date.  In the case of any other Special
Payments, such notice shall be mailed as soon as practicable after the Trustee
has confirmed that it has received funds for such Special Payment, stating the
Special Distribution Date for such Special Payment which shall occur not less
than 15 days after the date of such notice and as soon as practicable
thereafter.  Notices mailed by the Trustee shall set forth:

                 (i)      the Special Distribution Date and the Record Date
         therefor (except as otherwise provided in Section 11.01);
<PAGE>   38
                                       32

                 (ii)     the amount of the Special Payment for each $1,000
         face amount Certificate and the amount thereof constituting principal,
         premium, if any, and interest;

                 (iii)    the reason for the Special Payment; and

                 (iv)     if the Special Distribution Date is the same date as
         a Regular Distribution Date for the Certificates, the total amount to
         be received on such date for each $1,000 face amount Certificate.

If the amount of (i) premium, if any, payable upon the redemption or purchase
of an Equipment Note or (ii) the Special Redemption Premium, if any, has not
been calculated at the time that the Trustee mails notice of a Special Payment,
it shall be sufficient if the notice sets forth the other amounts to be
distributed and states that any premium received will also be distributed.

                 If any redemption of the Equipment Notes held in any Trust is
cancelled, the Trustee, as soon as possible after learning thereof, shall cause
notice thereof to be mailed to each Certificateholder at its address as it
appears on the Register.

                 Section 4.03.  Statements to Certificateholders.  (a)  On each
Regular Distribution Date and Special Distribution Date, the Trustee will
include with each distribution of a Scheduled Payment or Special Payment, as
the case may be, to Certificateholders a statement setting forth the
information provided below (in the case of a Special Payment, including any
Special Redemption Premium, reflecting in part the information provided by the
Escrow Paying Agent under the Escrow Agreement).  Such statement shall set
forth (per $1,000 aggregate principal amount of Certificate as to (ii), (iii),
(iv) and (v) below) the following information:

                 (i)      the aggregate amount of funds distributed on such
         Distribution Date under the Agreement and under the Escrow Agreement,
         indicating the amount allocable to each source;

                 (ii)     the amount of such distribution under this Agreement
         allocable to principal and the amount allocable to premium (including
         the Special Redemption Premium), if any;

                 (iii)    the amount of such distribution under this Agreement
         allocable to interest;

                 (iv)     the amount of such distribution under the Escrow
         Agreement allocable to interest;
<PAGE>   39
                                       33


                 (v)      the amount of such distribution under the Escrow
         Agreement allocable to Deposits; and

                 (vi)     the Pool Balance and the Pool Factor.

                 With respect to the Certificates registered in the name of a
Clearing Agency or its nominee, on the Record Date prior to each Distribution
Date, the Trustee will request from the Clearing Agency a securities position
listing setting forth the names of all Clearing Agency Participants reflected
on the Clearing Agency's books as holding interests in the Certificates on such
Record Date.  On each Distribution Date, the Trustee will mail to each such
Clearing Agency Participant the statement described above and will make
available additional copies as requested by such Clearing Agency Participant
for forwarding to holders of interests in the Certificates.

                 (b)      Within a reasonable period of time after the end of
each calendar year but not later than the latest date permitted by law, the
Trustee shall furnish to each Person who at any time during such calendar year
was a Certificateholder of record a statement containing the sum of the amounts
determined pursuant to clauses (a)(i), (a)(ii), (a)(iii), (a)(iv) and (a)(v)
above with respect to the related Trust for such calendar year or, in the event
such Person was a Certificateholder of record during a portion of such calendar
year, for the applicable portion of such year, and such other items as are
readily available to the Trustee and which a Certificateholder shall reasonably
request as necessary for the purpose of such Certificateholder's preparation of
its federal income tax returns.  Such statement and such other items shall be
prepared on the basis of information supplied to the Trustee by the Clearing
Agency Participants and shall be delivered by the Trustee to such Clearing
Agency Participants to be available for forwarding by such Clearing Agency
Participants to the holders of interests in the Certificates in the manner
described in Section 4.03(a).

                 (c)      Promptly following (i) the Transfer Date, if there
has been any change in the information set forth in clauses (x), (y) and (z)
below from that set forth in page 65 of the Offering Memorandum, and (ii) any
early redemption or purchase of, or any default in the payment of principal or
interest in respect of, any of the Equipment Notes held in the Trust, or any
Final Withdrawal, the Trustee shall furnish to Certificateholders of record on
such date a statement setting forth (x) the expected Pool Balances for each
subsequent Regular Distribution Date following the Transfer Date, (y) the
related Pool Factors for such Regular Distribution Dates and (z) the expected
principal distribution schedule of the Equipment Notes, in the aggregate, held
as Trust Property at the date of such notice.  With respect to the Certificates
registered in the name of a Clearing Agency, on the Transfer Date, the Trustee
will request from such Clearing Agency a securities position listing setting
forth the names of all Clearing Agency Participants reflected on such Clearing
Agency's books as holding interests in the Certificates on such date.  The
Trustee will mail to each such Clearing Agency Participant the statement
described above and will make available additional
<PAGE>   40
                                       34

copies as requested by such Clearing Agency Participant for forwarding to
holders of interests in the Certificates.

                 Section 4.04.  Investment of Special Payment Moneys.  Any
money received by the Trustee pursuant to Section 4.01(b) representing a
Special Payment which is not distributed on the date received shall, to the
extent practicable, be invested in Permitted Investments by the Trustee pending
distribution of such Special Payment pursuant to Section 4.02.  Any investment
made pursuant to this Section 4.04 shall be in such Permitted Investments
having maturities not later than the date that such moneys are required to be
used to make the payment required under Section 4.02 on the applicable Special
Distribution Date and the Trustee shall hold any such Permitted Investments
until maturity.  The Trustee shall have no liability with respect to any
investment made pursuant to this Section 4.04, other than by reason of the
willful misconduct or negligence of the Trustee.  All income and earnings from
such investments shall be distributed on such Special Distribution Date as part
of such Special Payment.


                                   ARTICLE V

                                  THE COMPANY

                 Section 5.01.  Maintenance of Corporate Existence.  The
Company, at its own cost and expense, will do or cause to be done all things
necessary to preserve and keep in full force and effect its corporate
existence, rights and franchises, except as otherwise specifically permitted in
Section 5.02; provided, however, that the Company shall not be required to
preserve any right or franchise if the Company shall determine that the
preservation thereof is no longer desirable in the conduct of the business of
the Company.

                 Section 5.02.  Consolidation, Merger, Etc.  The Company shall
not consolidate with or merge into any other corporation or convey, transfer or
lease substantially all of its assets as an entirety to any Person unless:

                 (a)      the corporation formed by such consolidation or into
         which the Company is merged or the Person that acquires by conveyance,
         transfer or lease substantially all of the assets of the Company as an
         entirety shall be (i) organized and validly existing under the laws of
         the United States of America or any state thereof or the District of
         Columbia, (ii) a "citizen of the United States" as defined in 49
         U.S.C. Section 40102(a)(15), as amended, and (iii) a United States
         certificated air carrier, if and so long as such status is a condition
         of entitlement to the benefits of Section 1110 of the Bankruptcy
         Reform Act of 1978, as amended (11 U.S.C. Section  1110), with respect
         to the Leases or the Aircraft owned by the Company;
<PAGE>   41
                                       35

                 (b)      the corporation formed by such consolidation or into
         which the Company is merged or the Person which acquires by
         conveyance, transfer or lease substantially all of the assets of the
         Company as an entirety shall execute and deliver to the Trustee
         applicable to the Certificates a duly authorized, valid, binding and
         enforceable agreement in form and substance reasonably satisfactory to
         the Trustee containing an assumption by such successor corporation or
         Person of the due and punctual performance and observance of each
         covenant and condition of the Note Documents and of this Agreement
         applicable to the Certificates to be performed or observed by the
         Company; and

                 (c)      the Company shall have delivered to the Trustee an
         Officer's Certificate of the Company and an Opinion of Counsel of the
         Company reasonably satisfactory to the Trustee, each stating that such
         consolidation, merger, conveyance, transfer or lease and the
         assumption agreement mentioned in clause (b) above comply with this
         Section 5.02 and that all conditions precedent herein provided for
         relating to such transaction have been complied with.

                 Upon any consolidation or merger, or any conveyance, transfer
or lease of substantially all of the assets of the Company as an entirety in
accordance with this Section 5.02, the successor corporation or Person formed
by such consolidation or into which the Company is merged or to which such
conveyance, transfer or lease is made shall succeed to, and be substituted for,
and may exercise every right and power of, the Company under this Agreement
applicable to the Certificates with the same effect as if such successor
corporation or Person had been named as the Company herein.  No such
conveyance, transfer or lease of substantially all of the assets of the Company
as an entirety shall have the effect of releasing any successor corporation or
Person which shall have become such in the manner prescribed in this Section
5.02 from its liability in respect of this Agreement and any Note Document
applicable to the Certificates to which it is a party.


                                   ARTICLE VI

                                    DEFAULT

                 Section 6.01.  Events of Default.  (a)  Exercise of Remedies.
Upon the occurrence and during the continuation of any Indenture Default under
any Indenture, the Trustee may, to the extent it is the Controlling Party at
such time (as determined pursuant to the Intercreditor Agreement), direct the
exercise of remedies as provided in the Intercreditor Agreement.
<PAGE>   42
                                       36

                 (b)      Purchase Rights of Certificateholders.  By acceptance
of its Certificate, each Certificateholder agrees that at any time after the
occurrence and during the continuation of a Triggering Event,

                 (i)      each Class B Certificateholder shall have the right
         to purchase all, but not less than all, of the Certificates upon ten
         days' written notice to the Trustee and each other Class B
         Certificateholder, provided that (A) if prior to the end of such
         ten-day period any other Class B Certificateholder notifies such
         purchasing Class B Certificateholder that such other Class B
         Certificateholder wants to participate in such purchase, then such
         other Class B Certificateholder may join with the purchasing Class B
         Certificateholder to purchase all, but not less than all, of the
         Certificates pro rata based on the Fractional Undivided Interest in
         the Class B Trust held by each such Class B Certificateholder and (B)
         if prior to the end of such ten-day period any other Class B
         Certificateholder fails to notify the purchasing Class B
         Certificateholder of such other Class B Certificateholder's desire to
         participate in such a purchase, then such other Class B
         Certificateholder shall lose its right to purchase the Certificates
         pursuant to this Section 6.01(b);

                 (ii)     each Class C Certificateholder shall have the right
         (which shall not expire upon any purchase of the Certificates pursuant
         to clause (i) above) to purchase all, but not less than all, of the
         Certificates and the Class B Certificates upon ten days' written
         notice to the Trustee, the Class B Trustee and each other Class C
         Certificateholder, provided that (A) if prior to the end of such
         ten-day period any other Class C Certificateholder notifies such
         purchasing Class C Certificateholder that such other Class C
         Certificateholder wants to participate in such purchase, then such
         other Class C Certificateholder may join with the purchasing Class C
         Certificateholder to purchase all, but not less than all, of the
         Certificates and the Class B Certificates pro rata based on the
         Fractional Undivided Interest in the Class C Trust held by each such
         Class C Certificateholder and (B) if prior to the end of such ten-day
         period any other Class C Certificateholder fails to notify the
         purchasing Class C Certificateholder of such other Class C
         Certificateholder's desire to participate in such a purchase, then
         such other Class C Certificateholder shall lose its right to purchase
         the Certificates pursuant to this Section 6.01(b); and

                 (iii)    each Class D Certificateholder shall have the right
         (which shall not expire upon any purchase of the Certificates pursuant
         to clause (i) or (ii) above) to purchase all, but not less than all,
         of the Certificates, the Class B Certificates and the Class C
         Certificates upon ten days' written notice to the Trustee, the Class B
         Trustee, the Class C Trustee and each other Class D Certificateholder,
         provided that (A) if prior to the end of such ten-day period any other
         Class D Certificateholder notifies such purchasing Class D
         Certificateholder that such other Class D Certificateholder wants to
         participate in such purchase, then such other Class D
         Certificateholder may
<PAGE>   43
                                       37

         join with the purchasing Class D Certificateholder to purchase all,
         but not less than all, of the Certificates, the Class B Certificates
         and the Class C Certificates pro rata based on the Fractional
         Undivided Interest in the Class D Trust held by each such Class D
         Certificateholder and (B) if prior to the end of such ten-day period
         any other Class D Certificateholder fails to notify the purchasing
         Class D Certificateholder of such other Class D Certificateholder's
         desire to participate in such a purchase, then such other Class D
         Certificateholder shall lose its right to purchase the Certificates
         pursuant to this Section 6.01(b).

                 The purchase price with respect to the Certificates shall be
equal to the Pool Balance of the Certificates, together with accrued and unpaid
interest thereon to the date of such purchase, without premium, but including
any other amounts then due and payable to the Certificateholders under this
Agreement, the Intercreditor Agreement, the Escrow Agreement or any Note
Document or on or in respect of the Certificates; provided, however, that (i)
if such purchase occurs after the record date specified in Section 2.03(b) of
the Escrow Agreement relating to the distribution of unused Deposits and
accrued and unpaid interest thereunder, such purchase price shall be reduced by
the aggregate amount of unused Deposits and interest to be distributed under
the Escrow Agreement (which deducted amounts shall remain distributable to, and
may be retained by, the Certificateholder as of such Record Date) and (ii) if
such purchase occurs after a Record Date, such purchase price shall be reduced
by the amount to be distributed hereunder on the related Distribution Date
(which deducted amounts shall remain distributable to, and may be retained by,
the Certificateholder as of such Record Date); provided further that no such
purchase of Certificates shall be effective unless the purchaser(s) shall
certify to the Trustee that contemporaneously with such purchase, such
purchaser(s) is purchasing, pursuant to the terms of this Agreement and the
Other Agreements, the Certificates, the Class B Certificates and the Class C
Certificates which are senior to the securities held by such purchaser(s).
Each payment of the purchase price of the Certificates referred to in the first
sentence hereof shall be made to an account or accounts designated by the
Trustee and each such purchase shall be subject to the terms of this Section
6.01(b).  Each Certificateholder agrees by its acceptance of its Certificate
that it will, subject to Section 3.04 of this Agreement, upon payment from such
Class B Certificateholder(s), Class C Certificateholder(s) or Class D
Certificateholder(s), as the case may be, of the purchase price set forth in
the first sentence of this paragraph, forthwith sell, assign, transfer and
convey to the purchaser(s) thereof (without recourse, representation or
warranty of any kind except for its own acts), all of the right, title,
interest and obligation of such Certificateholder in this Agreement, the Escrow
Agreement, the Deposit Agreement, the Intercreditor Agreement, the Liquidity
Facilities, the Note Documents and all Certificates and Escrow Receipts held by
such Certificateholder (excluding all right, title and interest under any of
the foregoing to the extent such right, title or interest is with respect to an
obligation not then due and payable as respects any action or inaction or state
of affairs occurring prior to such sale) and the purchaser shall assume all of
such Certificateholder's obligations under this Agreement, the Escrow
Agreement, the Deposit Agreement, the Intercreditor
<PAGE>   44
                                       38

Agreement, the Liquidity Facilities, the Note Documents and all such
Certificates and Escrow Receipts.  The Certificates will be deemed to be
purchased on the date payment of the purchase price is made notwithstanding the
failure of the Certificateholders to deliver any Certificates and, upon such a
purchase, (i) the only rights of the Certificateholders will be to deliver the
Certificates to the purchaser(s) and receive the purchase price for such
Certificates and (ii) if the purchaser(s) shall so request, such
Certificateholder will comply with all the provisions of Section 3.04 of this
Agreement to enable new Certificates to be issued to the purchaser in such
denominations as it shall request.  All charges and expenses in connection with
the issuance of any such new Certificates shall be borne by the purchaser
thereof.

                 As used in this Section 6.01, the terms "Class B
Certificateholder", "Class B Trust", "Class B Certificate", "Class B Trustee",
"Class C Certificate", "Class C Certificateholder", "Class C Trust", "Class C
Trustee", "Class D Certificateholder" and "Class D Trust", shall have the
respective meanings assigned to such terms in the Intercreditor Agreement.

                 Section 6.02.  Incidents of Sale of Equipment Notes.  Upon any
sale of all or any part of the Equipment Notes held in the Trust made either
under the power of sale given under this Agreement or otherwise for the
enforcement of this Agreement, the following shall be applicable:

                 (a)      Certificateholders and Trustee May Purchase Equipment
         Notes.  Any Certificateholder, the Trustee in its individual or any
         other capacity or any other Person may bid for and purchase any of the
         Equipment Notes held in the Trust, and upon compliance with the terms
         of sale, may hold, retain, possess and dispose of such Equipment Notes
         in their own absolute right without further accountability.

                 (b)      Receipt of Trustee Shall Discharge Purchaser.  The
         receipt of the Trustee making such sale shall be a sufficient
         discharge to any purchaser for his purchase money, and, after paying
         such purchase money and receiving such receipt, such purchaser or its
         personal representative or assigns shall not be obliged to see to the
         application of such purchase money, or be in any way answerable for
         any loss, misapplication or nonapplication thereof.

                 (c)      Application of Moneys Received upon Sale.  Any moneys
         collected by the Trustee upon any sale made either under the power of
         sale given by this Agreement or otherwise for the enforcement of this
         Agreement shall be applied as provided in Section 4.02.

                 Section 6.03.  Judicial Proceedings Instituted by Trustee;
Trustee May Bring Suit.  If there shall be a failure to make payment of the
principal of, premium, if any, or
<PAGE>   45
                                       39

interest on any Equipment Note held in the Trust, or if there shall be any
failure to pay Rent (as defined in the relevant Lease) under any Lease when due
and payable, then the Trustee, in, its own name and as trustee of an express
trust, as holder of such Equipment Notes, to the extent permitted by and in
accordance with the terms of any related Intercreditor Agreement and any
related Note Documents (subject to rights of the applicable Owner Trustee or
Owner Participant to cure any such failure to pay principal of, premium, if
any, or interest on any Equipment Note or to pay Rent under any Lease in
accordance with the applicable Indenture), shall be entitled and empowered to
institute any suits, actions or proceedings at law, in equity or otherwise, for
the collection of the sums so due and unpaid on such Equipment Notes or under
such Lease and may prosecute any such claim or proceeding to judgment or final
decree with respect to the whole amount of any such sums so due and unpaid.

                 Section 6.04.  Control by Certificateholders.  Subject to
Section 6.03 and the Intercreditor Agreement, the Certificateholders holding
Certificates evidencing Fractional Undivided Interests aggregating not less
than a majority in interest in the related Trust shall have the right to direct
the time, method and place of conducting any proceeding for any remedy
available to the Trustee with respect to the Trust or pursuant to the terms of
the Intercreditor Agreement, or exercising any trust or power conferred on the
Trustee under this Agreement or the Intercreditor Agreement, including any
right of the Trustee as Controlling Party under the Intercreditor Agreement or
as holder of the Equipment Notes held in the related Trust; provided, however,
that

                 (a)      such Direction shall not in the opinion of the
         Trustee be in conflict with any rule of law or with this Agreement and
         would not involve the Trustee in personal liability or expense,

                 (b)      the Trustee shall not determine that the action so
         directed would be unjustly prejudicial to the Certificateholders not
         taking part in such Direction, and

                 (c)      the Trustee may take any other action deemed proper
         by the Trustee which is not inconsistent with such Direction.

                 Section 6.05.  Waiver of Past Defaults.  Subject to any
related Intercreditor Agreement, the Certificateholders holding Certificates of
a series evidencing Fractional Undivided Interests aggregating not less than a
majority in interest in the Trust (i) may on behalf of all of the
Certificateholders waive any past Event of Default hereunder and its
consequences or (ii) if the Trustee is the Controlling Party, may direct the
Trustee to instruct the applicable Loan Trustee to waive any past Indenture
Event of Default under any related Indenture and its consequences, and thereby
annul any Direction given by such Certificateholders or the Trustee to such
Loan Trustee with respect thereto, except a default:
<PAGE>   46
                                       40

                 (a)      in the deposit of any Scheduled Payment or Special
         Payment under Section 4.01 or in the distribution of any payment under
         Section 4.02 on the Certificates, or

                 (b)      in the payment of the principal of (premium, if any)
         or interest on the Equipment Notes held in the Trust, or

                 (c)      in respect of a covenant or provision hereof which
         under Article IX hereof cannot be modified or amended without the
         consent of each Certificateholder holding an Outstanding Certificate
         of a series affected thereby.

Upon any such waiver, such default shall cease to exist with respect to the
Certificates and any Event of Default arising therefrom shall be deemed to have
been cured for every purpose and any direction given by the Trustee on behalf
of the Certificateholders to the relevant Loan Trustee shall be annulled with
respect thereto; but no such waiver shall extend to any subsequent or other
default or Event of Default or impair any right consequent thereon.  Upon any
such waiver, the Trustee shall vote the Equipment Notes issued under the
relevant Indenture to waive the corresponding Indenture Event of Default.

                 Section 6.06.  Right of Certificateholders to Receive Payments
Not to Be Impaired.  Anything in this Agreement to the contrary
notwithstanding, including, without limitation, Section 6.07 hereof, but
subject to the Intercreditor Agreement, the right of any Certificateholder to
receive distributions of payments required pursuant to Section 4.02 hereof on
the applicable Certificates when due, or to institute suit for the enforcement
of any such payment on or after the applicable Regular Distribution Date or
Special Distribution Date, shall not be impaired or affected without the
consent of such Certificateholder.

                 Section 6.07.  Certificateholders May Not Bring Suit Except
Under Certain Conditions.  A Certificateholder shall not have the right to
institute any suit, action or proceeding at law or in equity or otherwise with
respect to this Agreement, for the appointment of a receiver or for the
enforcement of any other remedy under this Agreement, unless:

                 (a)      such Certificateholder previously shall have given
         written notice to the Trustee of a continuing Event of Default;

                 (b)      Certificateholders holding Certificates evidencing
         Fractional Undivided Interests aggregating not less than 25% of the
         related Trust shall have requested the Trustee in writing to institute
         such action, suit or proceeding and shall have offered to the Trustee
         indemnity as provided in Section 7.03(e);
<PAGE>   47
                                       41

                 (c)      the Trustee shall have refused or neglected to
         institute any such action, suit or proceeding for 60 days after
         receipt of such notice, request and offer of indemnity; and

                 (d)      no direction inconsistent with such written request
         shall have been given to the Trustee during such 60-day period by
         Certificateholders holding Certificates evidencing Fractional
         Undivided Interests aggregating not less than a majority in interest
         in the Trust.

                 It is understood and intended that no one or more of the
Certificateholders shall have any right in any manner whatsoever hereunder or
under the related Trust Supplement or under the Certificates to (i) surrender,
impair, waive, affect, disturb or prejudice any property in the Trust Property
of the Trust, or the lien of any related Indenture on any property subject
thereto, or the rights of the Certificateholders or the holders of the
Equipment Notes, (ii) obtain or seek to obtain priority over or preference with
respect to any other such Certificateholder or (iii) enforce any right under
this Agreement, except in the manner herein provided and for the equal, ratable
and common benefit of all the Certificateholders subject to the provisions of
this Agreement.

                 Section 6.08.  Remedies Cumulative.  Every remedy given
hereunder to the Trustee or to any of the Certificateholders shall not be
exclusive of any other remedy or remedies, and every such remedy shall be
cumulative and in addition to every other remedy given hereunder or now or
hereafter given by statute, law, equity or otherwise.

                 Section 6.09.  Undertaking for Costs.  In any suit for the
enforcement of any right or remedy under this Agreement, or in any suit against
the Trustee for any action taken, suffered or omitted by it as Trustee, a court
may require any party litigant in such suit to file an undertaking to pay the
costs of such suit, and may assess costs against any such party litigant, in
the manner and to the extent provided in the Trust Indenture Act; provided,
however, that neither this Section 6.09 nor the Trust Indenture Act shall be
deemed to authorize any court to require such an undertaking or to make such an
assessment in any suit instituted by the Company.


                                  ARTICLE VII

                                  THE TRUSTEE

                 Section 7.01.  Certain Duties and Responsibilities.  (a)
Except during the continuance of an Event of Default in respect of a Trust, the
Trustee undertakes to perform such duties in respect of the Trust as are
specifically set forth in this Agreement, and no implied covenants or
obligations shall be read into this Agreement against the Trustee.
<PAGE>   48
                                       42


                 (b)      In case an Event of Default in respect of a Trust has
occurred and is continuing, the Trustee shall exercise such of the rights and
powers vested in it by this Agreement in respect of the Trust, and use the same
degree of care and skill in their exercise, as a prudent man would exercise or
use under the circumstances in the conduct of his own affairs.

                 (c)      No provision of this Agreement shall be construed to
relieve the Trustee from liability for its own negligent action, its own
negligent failure to act, or its own willful misconduct, except that

                 (i)      this Subsection shall not be construed to limit the
         effect of Subsection (a) of this Section 7.01; and

                 (ii)     the Trustee shall not be liable for any error of
         judgment made in good faith by a Responsible Officer of the Trustee,
         unless it shall be proved that the Trustee was negligent in
         ascertaining the pertinent facts.

                 (d)      Whether or not herein expressly so provided, every
provision of this Agreement relating to the conduct or affecting the liability
of or affording protection to the Trustee shall be subject to the provisions of
this Section 7.01.

                 Section 7.02.  Notice of Defaults.  As promptly as practicable
after, and in any event within 90 days after, the occurrence of any default (as
such term is defined below) hereunder known to the Trustee, the Trustee shall
transmit by mail to the Company, any Owner Trustees, the Owner Participants,
the Loan Trustees and the Certificateholders holding Certificates in accordance
with Section 313(c) of the Trust Indenture Act, notice of such default
hereunder known to the Trustee, unless such default shall have been cured or
waived; provided, however, that, except in the case of a default in the payment
of the principal, premium, if any, or interest on any Equipment Note, the
Trustee shall be protected in withholding such notice if and so long as the
board of directors, the executive committee or a trust committee of directors
and/or Responsible Officers of the Trustee in good faith shall determine that
the withholding of such notice is in the interests of the Certificateholders.
For the purpose of this Section 7.02 in respect of any Trust, the term
"default" means any event that is, or after notice or lapse of time or both
would become, an Event of Default in respect of that Trust.

                 Section 7.03.  Certain Rights of Trustee.  Subject to the
provisions of Section 315 of the Trust Indenture Act:

                 (a)      the Trustee may rely and shall be protected in acting
         or refraining from acting in reliance upon any resolution,
         certificate, statement, instrument, opinion, report, notice, request,
         direction, consent, order, bond, debenture or other paper or
<PAGE>   49
                                       43

         document believed by it to be genuine and to have been signed or
         presented by the proper party or parties;

                 (b)      any request or direction of the Company mentioned
         herein shall be sufficiently evidenced by a Request;

                 (c)      whenever in the administration of this Agreement or
         the Intercreditor Agreement, the Trustee shall deem it desirable that
         a matter be proved or established prior to taking, suffering or
         omitting any action hereunder, the Trustee (unless other evidence be
         herein specifically prescribed) may, in the absence of bad faith on
         its part, rely upon an Officer's Certificate of the Company, any Owner
         Trustee or any Loan Trustee;

                 (d)      the Trustee may consult with counsel and the advice
         of such counsel or any Opinion of Counsel shall be full and complete
         authorization and protection in respect of any action taken, suffered
         or omitted by it hereunder in good faith and in reliance thereon;

                 (e)      the Trustee shall be under no obligation to exercise
         any of the rights or powers vested in it by this Agreement or the
         Intercreditor Agreement at the Direction of any of the
         Certificateholders pursuant to this Agreement or the Intercreditor
         Agreement, unless the Certificateholders shall have offered to the
         Trustee reasonable security or indemnity against the cost, expenses
         and liabilities which might be incurred by it in compliance with such
         Direction;

                 (f)      the Trustee shall not be bound to make any
         investigation into the facts or matters stated in any resolution,
         certificate, statement, instrument, opinion, report, notice, request,
         direction, consent, order, bond, debenture or other paper or document;

                 (g)      the Trustee may execute any of the trusts or powers
         under this Agreement or the Intercreditor Agreement or perform any
         duties under this Agreement or the Intercreditor Agreement either
         directly or by or through agents or attorneys, and the Trustee shall
         not be responsible for any misconduct or negligence on the part of any
         agent or attorney appointed with due care by it under this Agreement
         or the Intercreditor Agreement;

                 (h)      the Trustee shall not be liable with respect to any
         action taken or omitted to be taken by it in good faith in accordance
         with the Direction of the Certificateholders holding Certificates
         evidencing Fractional Undivided Interests aggregating not less than a
         majority in interest in the Trust relating to the time, method and
         place of conducting any proceeding for any remedy available to the
<PAGE>   50
                                       44

         Trustee, or exercising any trust or power conferred upon the Trustee,
         under this Agreement or the Intercreditor Agreement; and

                 (i)      the Trustee shall not be required to expend or risk
         its own funds in the performance of any of its duties under this
         Agreement, or in the exercise of any of its rights or powers, if it
         shall have reasonable grounds for believing that repayment of such
         funds or adequate indemnity against such risk is not reasonably
         assured to it.

                 Section 7.04.  Not Responsible for Recitals or Issuance of
Certificates.  The recitals contained herein and in the Certificates, except
the certificates of authentication, shall not be taken as the statements of the
Trustee, and the Trustee assumes no responsibility for their correctness.
Subject to Section 7.15, the Trustee makes no representations as to the
validity or sufficiency of this Agreement, any Equipment Notes, the
Intercreditor Agreement, the Deposit Agreement, the Escrow Agreement, the
Certificates, or any Note Documents, except that the Trustee hereby represents
and warrants that this Agreement has been, and the Registration Rights
Agreement, each Certificate, the Note Purchase Agreement, the Escrow Agreement
and the Intercreditor Agreement will be, executed and delivered by one of its
officers who is duly authorized to execute and deliver such document on its
behalf.

                 Section 7.05.  May Hold Certificates.  The Trustee, any Paying
Agent, Registrar or any of their Affiliates or any other agent, in their
respective individual or any other capacity, may become the owner or pledgee of
Certificates and, subject to Sections 310(b) and 311 of the Trust Indenture
Act, if applicable, may otherwise deal with the Company, any Owner Trustees or
the Loan Trustees with the same rights it would have if it were not Trustee,
Paying Agent, Registrar or such other agent.

                 Section 7.06.  Money Held in Trust.  Money held by the Trustee
or the Paying Agent in trust under this Agreement need not be segregated from
other funds except to the extent required herein or by law and neither the
Trustee nor the Paying Agent shall have any liability for interest upon any
such moneys except as provided for herein.

                 Section 7.07.  Compensation and Reimbursement.  The Company
agrees:

                 (a)      to pay, or cause to be paid, to the Trustee from time
         to time  reasonable compensation for all services rendered by it
         hereunder (which compensation shall not be limited by any provision of
         law in regard to the compensation of a trustee of an express trust);
         and

                 (b)      to reimburse, or cause to be reimbursed, the Trustee
         upon its request for all reasonable out- of-pocket expenses,
         disbursements and advances incurred or made by the Trustee in
         accordance with any provision of this Agreement or the Intercreditor
         Agreement (including the reasonable compensation and the expenses and
<PAGE>   51
                                       45

         disbursements of its agents and counsel), except any such expense,
         disbursement or advance as may be attributable to its negligence,
         willful misconduct or bad faith or as may be incurred due to the
         Trustee's breach of its representations and warranties set forth in
         Section 7.15; and

                 (c)      to indemnify the Trustee with respect to the
         Certificates, pursuant to Section 8.1 of the Owned Aircraft
         Participation Agreements and Section 9.1 of the Leased Aircraft
         Participation Agreements, as the case may be.

                 The Trustee shall be entitled to reimbursement from, and shall
have a lien prior to the Certificates upon, all property and funds held or
collected by the Trustee in its capacity as Trustee for any tax incurred
without negligence, bad faith or willful misconduct, on its part, arising out
of or in connection with the acceptance or administration of the Trust (other
than any tax attributable to the Trustee's compensation for serving as such),
including any costs and expenses incurred in contesting the imposition of any
such tax.  The Trustee shall notify the Company of any claim for any tax for
which it may seek reimbursement.  If the Trustee reimburses itself from the
Trust Property of such Trust for any such tax, it will mail a brief report
within 30 days setting forth the amount of such tax and the circumstances
thereof to all Certificateholders as their names and addresses appear in the
Register.

                 Section 7.08.  Corporate Trustee Required; Eligibility.  The
Trust shall at all times have a Trustee which shall be eligible to act as a
trustee under Section 310(a) of the Trust Indenture Act and shall have a
combined capital and surplus of at least $75,000,000 (or a combined capital and
surplus in excess of $5,000,000 and the obligations of which, whether now in
existence or hereafter incurred, are fully and unconditionally guaranteed by a
corporation organized and doing business under the laws of the United States,
any state or territory thereof or of the District of Columbia and having a
combined capital and surplus of at least $75,000,000).  If such corporation
publishes reports of conditions at least annually, pursuant to law or to the
requirements of federal, state, territorial or District of Columbia supervising
or examining authority, then for the purposes of this Section 7.08 the combined
capital and surplus of such corporation shall be deemed to be its combined
capital and surplus as set forth in its most recent report of conditions so
published.

                 In case at any time the Trustee shall cease to be eligible in
accordance with the provisions of this Section 7.08 to act as Trustee of the
Trust, the Trustee shall resign immediately as Trustee of the Trust in the
manner and with the effect specified in Section 7.09.

                 Section 7.09.  Resignation and Removal; Appointment of
Successor.  (a)  No resignation or removal of the Trustee and no appointment of
a successor Trustee of the Trust pursuant to this Article shall become
effective until the acceptance of appointment by the successor Trustee under
Section 7.10.
<PAGE>   52
                                       46


                 (b)      The Trustee may resign at any time as Trustee of the
Trust by giving prior written notice thereof to the Company, the Authorized
Agents, the Owner Trustees and the Loan Trustees.  If an instrument of
acceptance by a successor Trustee shall not have been delivered to the Company,
the Owner Trustees and the Trustee within 30 days after the giving of such
notice of resignation, the resigning Trustee may petition any court of
competent jurisdiction for the appointment of a successor Trustee.

                 (c)      The Trustee may be removed at any time by Direction
of the Certificateholders holding Certificates evidencing Fractional Undivided
Interests aggregating not less than a majority in interest in such Trust
delivered to the Trustee and to the Company, the Owner Trustees and the Loan
Trustees.

                 (d)      If at any time in respect of the Trust:

                 (i)      the Trustee shall fail to comply with Section 310 of
         the Trust Indenture Act, if applicable, after written request therefor
         by the Company or by any Certificateholder who has been a bona fide
         Certificateholder for at least six months; or

                 (ii)     the Trustee shall cease to be eligible under Section
         7.08 and shall fail to resign after written request therefor by the
         Company or by any such Certificateholder; or

                 (iii)    the Trustee shall become incapable of acting or shall
         be adjudged a bankrupt or insolvent, or a receiver of the Trustee or
         of its property shall be appointed or any public officer shall take
         charge or control of the Trustee or of its property or affairs for the
         purpose of rehabilitation, conservation or liquidation;

then, in any case, (i) the Company may remove the Trustee or (ii) any
Certificateholder who has been a bona fide Certificateholder for at least six
months may, on behalf of itself and all others similarly situated, petition any
court of competent jurisdiction for the removal of the Trustee and the
appointment of a successor Trustee of the Trust.

                 (e)      If a Responsible Officer of the Trustee shall obtain
actual knowledge of an Avoidable Tax (as defined below) in respect of any Trust
which has been or is likely to be asserted, the Trustee shall promptly notify
the Company and shall, within 30 days of such notification, resign as Trustee
of such Trust hereunder unless within such 30-day period the Trustee shall have
received notice that the Company has agreed to pay such tax.  The Company shall
promptly appoint a successor Trustee of such Trust in a jurisdiction where
there are no Avoidable Taxes.  As used herein, an "Avoidable Tax" in respect of
such Trust means a state or local tax:  (i) upon (w) such Trust, (x) such Trust
Property, (y) Certificateholders of the Trust or (z) the Trustee for which the
Trustee is entitled to seek
<PAGE>   53
                                       47

reimbursement from the Trust Property of such Trust, and (ii) which would be
avoided if the Trustee were located in another state, or jurisdiction within a
state, within the United States of America.  A tax shall not be an Avoidable
Tax in respect of any Trust if the Company or any Owner Trustee shall agree to
pay, and shall pay, such tax.

                 (f)      If the Trustee shall resign, be removed or become
incapable of acting as Trustee of the Trust or if a vacancy shall occur in the
office of the Trustee of the Trust for any cause, the Company shall promptly
appoint a successor Trustee.  If, within one year after such resignation,
removal or incapability, or other occurrence of such vacancy, a successor
Trustee shall be appointed by Direction of the Certificateholders holding
Certificates evidencing Fractional Undivided Interests aggregating not less
than a majority in interest in such Trust delivered to the Company, the Owner
Trustees, the Loan Trustee and the retiring Trustee, then the successor Trustee
so appointed shall, with the approval of the Company of such appointment, which
approval shall not be unreasonably withheld, forthwith upon its acceptance of
such appointment, become the successor Trustee and supersede the successor
Trustee appointed as provided above.  If no successor Trustee shall have been
so appointed as provided above and accepted appointment in the manner
hereinafter provided, the resigning Trustee or any Certificateholder who has
been a bona fide Certificateholder of the related series for at least six
months may, on behalf of himself and all others similarly situated, petition
any court of competent jurisdiction for the appointment of a successor Trustee.

                 (g)      The successor Trustee shall give notice of the
resignation and removal of the Trustee and appointment of the successor Trustee
by mailing written notice of such event by first-class mail, postage prepaid,
to the Certificateholders as their names and addresses appear in the Register.
Each notice shall include the name of such successor Trustee and the address of
its Corporate Trust Office.

                 Section 7.10.  Acceptance of Appointment by Successor.  Every
successor Trustee appointed hereunder shall execute and deliver to the Company
and to the retiring Trustee an instrument accepting such appointment, and
thereupon the resignation or removal of the retiring Trustee shall become
effective and such successor Trustee, without any further act, deed or
conveyance, shall become vested with all the rights, powers, trusts and duties
of the retiring Trustee; but, on request of the Company or the successor
Trustee, such retiring Trustee shall execute and deliver an instrument
transferring to such successor Trustee all such rights, powers and trusts of
the retiring Trustee and shall duly assign, transfer and deliver to such
successor Trustee all Trust Property held by such retiring Trustee, subject
nevertheless to its lien, if any, provided for in Section 7.07.  Upon request
of any such successor Trustee, the Company, the retiring Trustee and such
successor Trustee shall execute and deliver any and all instruments containing
such provisions as shall be necessary or desirable to transfer and confirm to,
and for more fully and certainly vesting in, such successor Trustee all such
rights, powers and trusts.
<PAGE>   54
                                       48


                 No institution shall accept its appointment as a Trustee
hereunder unless at the time of such acceptance such institution shall be
qualified and eligible under this Article VII.

                 Section 7.11.  Merger, Conversion, Consolidation or Succession
to Business.  Any corporation into which the Trustee may be merged or converted
or with which it may be consolidated, or any corporation resulting from any
merger, conversion or consolidation to which the Trustee shall be a party, or
any corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder;
provided, however, that such corporation shall be otherwise qualified and
eligible under this Article VII, without the execution or filing of any paper
or any further act on the part of any of the parties hereto.  In case any
Certificates shall have been executed or authenticated, but not delivered, by
the Trustee then in office, any successor by merger, conversion or
consolidation to such authenticating Trustee may adopt such execution or
authentication and deliver the Certificates so executed or authenticated with
the same effect as if such successor Trustee had itself executed or
authenticated such Certificates.

                 Section 7.12.  Maintenance of Agencies.  (a)  With respect to
each series of Certificates, there shall at all times be maintained an office
or agency in the location set forth in Section 12.04 where Certificates may be
presented or surrendered for registration of transfer or for exchange, and for
payment thereof, and where notices and demands, to or upon the Trustee in
respect of such Certificates or this Agreement may be served; provided,
however, that, if it shall be necessary that the Trustee maintain an office or
agency in another location with respect to the Certificates (e.g., the
Certificates shall be represented by Definitive Certificates and shall be
listed on a national securities exchange), the Trustee will make all reasonable
efforts to establish such an office or agency.  Written notice of the location
of each such other office or agency and of any change of location thereof shall
be given by the Trustee to the Company, any Owner Trustees, the Loan Trustees
(in the case of any Owner Trustee or Loan Trustee, at its address specified in
the Note Documents or such other address as may be notified to the Trustee) and
the Certificateholders.  In the event that no such office or agency shall be
maintained or no such notice of location or of change of location shall be
given, presentations and demands may be made and notices may be served at the
Corporate Trust Office of the Trustee.

                 (b)      There shall at all times be a Registrar and a Paying
Agent hereunder with respect to the Certificates.  Each such Authorized Agent
shall be a bank or trust company, shall be a corporation organized and doing
business under the laws of the United States or any state, with a combined
capital and surplus of at least $75,000,000, or a corporation having a combined
capital and surplus in excess of $5,000,000, the obligations of which are
guaranteed by a corporation organized and doing business under the laws of the
United States or any state, with a combined capital and surplus of at least
$75,000,000, and shall be authorized under such laws to exercise corporate
trust powers, subject to supervision by federal or state authorities.  The
Trustee shall initially be the Paying Agent and, as
<PAGE>   55
                                       49

provided in Section 3.04, Registrar hereunder with respect to the Certificates.
Each Registrar shall furnish to the Trustee, at stated intervals of not more
than six months, and at such other times as the Trustee may request in writing,
a copy of the Register maintained by such Registrar.

                 (c)      Any corporation into which any Authorized Agent may
be merged or converted or with which it may be consolidated, or any corporation
resulting from any merger, consolidation or conversion to which any Authorized
Agent shall be a party, or any corporation succeeding to the corporate trust
business of any Authorized Agent, shall be the successor of such Authorized
Agent, if such successor corporation is otherwise eligible under this Section
7.12, without the execution or filing of any paper or any further act on the
part of the parties hereto or such Authorized Agent or such successor
corporation.

                 (d)      Any Authorized Agent may at any time resign by giving
written notice of resignation to the Trustee, the Company, any Owner Trustees
and the Loan Trustees.  The Company may, and at the request of the Trustee
shall, at any time terminate the agency of any Authorized Agent by giving
written notice of termination to such Authorized Agent and to the Trustee.
Upon the resignation or termination of an Authorized Agent or in case at any
time any such Authorized Agent shall cease to be eligible under this Section
7.12 (when, in either case, no other Authorized Agent performing the functions
of such Authorized Agent shall have been appointed), the Company shall promptly
appoint one or more qualified successor Authorized Agents, reasonably
satisfactory to the Trustee, to perform the functions of the Authorized Agent
which has resigned or whose agency has been terminated or who shall have ceased
to be eligible under this Section 7.12.  The Company shall give written notice
of any such appointment made by it to the Trustee, any Owner Trustees and the
Loan Trustees; and in each case the Trustee shall mail notice of such
appointment to all Certificateholders as their names and addresses appear on
the Register for such series.

                 (e)      The Company agrees to pay, or cause to be paid, from
time to time to each Authorized Agent reasonable compensation for its services
and to reimburse it for its reasonable expenses.

                 Section 7.13.  Money for Certificate Payments to Be Held in
Trust.  All moneys deposited with any Paying Agent for the purpose of any
payment on Certificates shall be deposited and held in trust for the benefit of
the Certificateholders entitled to such payment, subject to the provisions of
this Section 7.13. Moneys so deposited and held in trust shall constitute a
separate trust fund for the benefit of the Certificateholders with respect to
which such money was deposited.

                 The Trustee may at any time, for the purpose of obtaining the
satisfaction and discharge of this Agreement or for any other purpose, direct
any Paying Agent to pay to the Trustee all sums held in trust by such Paying
Agent, such sums to be held by the Trustee
<PAGE>   56
                                       50

upon the same trusts as those upon which such sums were held by such Paying
Agent; and, upon such payment by any Paying Agent to the Trustee, such Paying
Agent shall be released from all further liability with respect to such money.

                 Section 7.14.  Registration of Equipment Notes in Trustee's
Name.  Subject to the provisions of any Intercreditor Agreement, the Trustee
agrees that all Equipment Notes to be purchased by any Trust and Permitted
Investments, if any, shall be issued in the name of the Trustee as trustee for
the applicable Trust or its nominee and held by the Trustee in trust for the
benefit of the Certificateholders, or, if not so held, the Trustee or its
nominee shall be reflected as the owner of such Equipment Notes or Permitted
Investments, as the case may be, in the register of the issuer of such
Equipment Notes or Permitted Investments, as the case may be.

                 Section 7.15.  Representations and Warranties of Trustee.  The
Trustee hereby represents and warrants, on the Transfer Date, that:

                 (a)      the Trustee is a Delaware banking corporation
         organized and validly existing in good standing under the laws of the
         State of Delaware;

                 (b)      the Trustee has full power, authority and legal right
         to receive the Trust Property assigned by the Related Trustee, assume
         the obligations under, and perform, the Assignment and Assumption
         Agreement, this Agreement, the Intercreditor Agreement, the Escrow
         Agreement and the Note Documents and has taken all necessary action to
         authorize such receipt, assumption and performance by it of this
         Agreement, the Intercreditor Agreement, the Escrow Agreement and the
         Note Documents to which it is a party;

                 (c)      the receipt of the Trust Property under the
         Assignment and Assumption Agreement and the performance by the Trustee
         of the Assignment and Assumption Agreement, this Trust Supplement, the
         Intercreditor Agreement, the Escrow Agreement and the Note Documents
         (i) will not violate any provision of any United States federal law or
         the law of the state of the United States where it is located
         governing the banking and trust powers of the Trustee or any order,
         writ, judgment, or decree of any court, arbitrator or governmental
         authority applicable to the Trustee or any of its assets, (ii) will
         not violate any provision of the articles of association or by-laws of
         the Trustee, and (iii) will not violate any provision of, or
         constitute, with or without notice or lapse of time, a default under,
         or result in the creation or imposition of any lien on any properties
         included in the Trust Property pursuant to the provisions of any
         mortgage, indenture, contract, agreement or other undertaking to which
         it is a party, which violation, default or lien could reasonably be
         expected to have an adverse effect on the Trustee's performance or
         ability to perform its duties hereunder or thereunder or on the
         transactions contemplated herein or therein;
<PAGE>   57
                                       51


                 (d)      the receipt of the Trust Property under the
         Assignment and Assumption Agreement and the performance by the Trustee
         of the Assignment and Assumption Agreement, this Agreement, the
         Intercreditor Agreement, the Escrow Agreement and the Note Documents
         will not require the authorization, consent, or approval of, the
         giving of notice to, the filing or registration with, or the taking of
         any other action in respect of, any governmental authority or agency
         of the United States or the state of the United States where it is
         located regulating the banking and corporate trust activities of the
         Trustee; and

                 (e)      The Assignment and Assumption Agreement has been duly
         executed and delivered by the Trustee and this Agreement, the
         Intercreditor Agreement, the Escrow Agreement and the Note Documents
         have been, or will be, as applicable, duly executed and delivered by
         the Trustee and constitute, or will constitute, as applicable, the
         legal, valid and binding agreements of the Trustee, enforceable
         against it in accordance with their respective terms; provided,
         however, that enforceability may be limited by (i) applicable
         bankruptcy, insolvency, reorganization, moratorium or similar laws
         affecting the rights of creditors generally and (ii) general
         principles of equity.

                 Section 7.16.  Withholding Taxes; Information Reporting.  As
to the Certificates, the Trustee, as trustee of the related grantor trust
created by this Agreement, shall exclude and withhold from each distribution of
principal, premium, if any, and interest and other amounts due under this
Agreement or under the Certificates any and all withholding taxes applicable
thereto as required by law.  The Trustee agrees to act as such withholding
agent and, in connection therewith, whenever any present or future taxes or
similar charges are required to be withheld with respect to any amounts payable
in respect of the Certificates, to withhold such amounts and timely pay the
same to the appropriate authority in the name of and on behalf of the
Certificateholders, that it will file any necessary withholding tax returns or
statements when due, and that, as promptly as possible after the payment
thereof, it will deliver to each such Certificateholder appropriate
documentation showing the payment thereof, together with such additional
documentary evidence as such Certificateholders may reasonably request from
time to time.  The Trustee agrees to file any other information reports as it
may be required to file under United States law.

                 Section 7.17.  Trustee's Liens.  The Trustee in its individual
capacity agrees that it will, in respect of each Trust created by this
Agreement, at its own cost and expense promptly take any action as may be
necessary to duly discharge and satisfy in full any mortgage, pledge, lien,
charge, encumbrance, security interest or claim ("Trustee's Liens") on or with
respect to the Trust Property of such Trust which is attributable to the
Trustee either (i) in its individual capacity and which is unrelated to the
transactions contemplated by this Agreement, the Intercreditor Agreement, the
Note Purchase Agreement or the Note
<PAGE>   58
                                       52

Documents or (ii) as Trustee hereunder or in its individual capacity and which
arises out of acts or omissions which are not contemplated by this Agreement.

                 Section 7.18.  Preferential Collection of Claims.  The Trustee
shall comply with Section 311(a) of the Trust Indenture Act, excluding any
creditor relationship listed in Section 311(b) of the Trust Indenture Act.  If
the Trustee shall resign or be removed as Trustee, it shall be subject to
Section 311(a) of the Trust Indenture Act to the extent provided therein.


                                  ARTICLE VIII

                CERTIFICATEHOLDERS' LISTS AND REPORTS BY TRUSTEE

                 Section 8.01.  The Company to Furnish Trustee with Names and
Addresses of Certificateholders.  The Company will furnish to the Trustee
within 15 days after each Record Date with respect to a Scheduled Payment, and
at such other times as the Trustee may request in writing within 30 days after
receipt by the Company of any such request, a list, in such form as the Trustee
may reasonably require, of all information in the possession or control of the
Company as to the names and addresses of the Certificateholders, in each case
as of a date not more than 15 days prior to the time such list is furnished;
provided, however, that so long as the Trustee is the sole Registrar, no such
list need be furnished; and provided further, however, that no such list need
be furnished for so long as a copy of the Register is being furnished to the
Trustee pursuant to Section 7.12.

                 Section 8.02.  Preservation of Information; Communications to
Certificateholders.  The Trustee shall preserve, in as current a form as is
reasonably practicable, the names and addresses of Certificateholders contained
in the most recent list furnished to the Trustee as provided in Section 7.12 or
Section 8.01, as the case may be, and the names and addresses of
Certificateholders of each series received by the Trustee in its capacity as
Registrar, if so acting.  The Trustee may destroy any list furnished to it as
provided in Section 7.12 or Section 8.01, as the case may be, upon receipt of a
new list so furnished.

                 Section 8.03.  Reports by Trustee.  Within 60 days after May
15 of each year commencing with the first full year following the issuance of
any series of Certificates, the Trustee shall transmit to the
Certificateholders, as provided in Section 313(c) of the Trust Indenture Act, a
brief report dated as of such May 15, if required by Section 313(a) of the
Trust Indenture Act.
<PAGE>   59
                                       53

                 Section 8.04.  Reports by the Company.  The Company shall:

                 (a)      file with the Trustee, within 30 days after the
         Company is required to file the same with the SEC, copies of the
         annual reports and of the information, documents and other reports (or
         copies of such portions of any of the foregoing as the SEC may from
         time to time by rules and regulations prescribe) which the Company is
         required to file with the SEC pursuant to section 13 or section 15(d)
         of the Securities Exchange Act of 1934, as amended; or, if the Company
         is not required to file information, documents or reports pursuant to
         either of such sections, then to file with the Trustee and the SEC, in
         accordance with rules and regulations prescribed by the SEC, such of
         the supplementary and periodic information, documents and reports
         which may be required pursuant to section 13 of the Securities
         Exchange Act of 1934, as amended, in respect of a security listed and
         registered on a national securities exchange as may be prescribed in
         such rules and regulations;

                 (b)      file with the Trustee and the SEC, in accordance with
         the rules and regulations prescribed by the SEC, such additional
         information, documents and reports with respect to compliance by the
         Company with the conditions and covenants of the Company provided for
         in this Agreement, as may be required by such rules and regulations,
         including, in the case of annual reports, if required by such rules
         and regulations, certificates or opinions of independent public
         accountants, conforming to the requirements of Section 1.02;

                 (c)      transmit to all Certificateholders, in the manner and
         to the extent provided in Section 313(c) of the Trust Indenture Act
         such summaries of any information, documents and reports required to
         be filed by the Company pursuant to subsections (a) and (b) of this
         Section 8.04 as may be required by rules and regulations prescribed by
         the SEC; and

                 (d)      furnish to the Trustee, not less often than annually,
         a brief certificate from the principal executive officer, principal
         financial officer or principal accounting officer as to his knowledge
         of the Company's compliance with all conditions and covenants under
         this Agreement (it being understood that for purposes of this
         paragraph (d), such compliance shall be determined without regard to
         any period of grace or requirement of notice provided under this
         Agreement).
<PAGE>   60
                                       54

                                   ARTICLE IX

                            SUPPLEMENTAL AGREEMENTS

                 Section 9.01.  Supplemental Agreements Without Consent of
Certificateholders.  Without the consent of the Certificateholders, the Company
may (but will not be required to), and the Trustee (subject to Section 9.03)
shall, at the Company's request, at any time and from time to time, enter into
one or more agreements supplemental hereto or to the Intercreditor Agreement,
the Escrow Agreement, the Note Purchase Agreement, the Deposit Agreement or a
Liquidity Facility, in form satisfactory to the Trustee, for any of the
following purposes:

                 (a)      to provide for the formation of a Trust, the issuance
         of a series of Certificates and other matters contemplated by Section
         2.01; or

                 (b)      to evidence the succession of another corporation to
         the Company and the assumption by any such successor of the covenants
         of the Company herein contained or of the Company's obligations under
         the Intercreditor Agreement, the Note Purchase Agreement, the
         Indemnity Agreement or any Liquidity Facility or to evidence the
         succession of another corporation to the Depositary or any Liquidity
         Provider and the assumption by any such successor of the obligations
         of the Depositary or such Liquidity Provider, as the case may be,
         under the Intercreditor Agreement, the Note Purchase Agreement, the
         Deposit Agreement, the Indemnity Agreement or any Liquidity Facility;
         or

                 (c)      to add to the covenants of the Company for the
         benefit of the Certificateholders, or to surrender any right or power
         conferred upon the Company in this Agreement, the Intercreditor
         Agreement, the Note Purchase Agreement or any Liquidity Facility; or

                 (d)      to correct or supplement any provision in this
         Agreement, the Intercreditor Agreement, the Escrow Agreement, the Note
         Purchase Agreement, the Deposit Agreement or any Liquidity Facility
         which may be defective or inconsistent with any other provision herein
         or therein or to cure any ambiguity or to modify any other provision
         with respect to matters or questions arising under this Agreement, the
         Intercreditor Agreement, the Escrow Agreement, the Note Purchase
         Agreement, the Deposit Agreement or any Liquidity Facility, provided,
         however, that any such action shall not materially adversely affect
         the interests of the Certificateholders; to correct any mistake in
         this Agreement, the Intercreditor Agreement or any Liquidity Facility;
         or, as provided in the Intercreditor Agreement, to give effect to or
         provide for a Replacement Liquidity Facility (as defined in the
         Intercreditor Agreement);  or
<PAGE>   61
                                       55

                 (e)      to comply with any requirement of the SEC, any
         applicable law, rules or regulations of any exchange or quotation
         system on which the Certificates are listed or of any regulatory body;
         or

                 (f)      to modify, eliminate or add to the provisions of this
         Agreement, the Intercreditor Agreement or any Liquidity Facility to
         such extent as shall be necessary to continue the qualification of
         this Agreement, the Intercreditor Agreement or any Liquidity Facility
         (including any supplemental agreement) under the Trust Indenture Act
         or under any similar Federal statute hereafter enacted, and to add to
         this Agreement, the Intercreditor Agreement or any Liquidity Facility
         such other provisions as may be expressly permitted by the Trust
         Indenture Act, excluding, however, the provisions referred to in
         Section 316(a)(2) of the Trust Indenture Act as in effect at the date
         as of which this Agreement was executed or any corresponding provision
         in any similar Federal statute hereafter enacted; or

                 (g)      to evidence and provide for the acceptance of
         appointment under this Agreement, the Intercreditor Agreement or any
         Liquidity Facility by a successor Trustee and to add to or change any
         of the provisions of this Agreement, the Intercreditor Agreement or
         any Liquidity Facility as shall be necessary to provide for or
         facilitate the administration of the Trust, pursuant to the
         requirements of Section 7.10; or

                 (h)      to provide the information required under Section
         7.12 and Section 12.04 as to the Trustee; or

                 (i)      to make any other amendments or modifications hereto,
         provided, however, that such amendments or modifications shall apply
         to Certificates to be thereafter issued;

provided, however, that no such supplemental agreement shall adversely affect
the status of any Trust as a grantor trust under Subpart E, Part I of
Subchapter J of Chapter 1 of Subtitle A of the Internal Revenue Code of 1986,
as amended, for U.S. federal income tax purposes.

                 Section 9.02.  Supplemental Agreements with Consent of
Certificateholders.  With respect to the Trust and the Certificates, with the
consent of the Certificateholders (including consents obtained in connection
with a tender offer or exchange offer for the Certificates) evidencing
Fractional Undivided Interests aggregating not less than a majority in interest
in such Trust, by Direction of said Certificateholders delivered to the Company
and the Trustee, the Company may (with the consent of the Owner Trustees, if
any, relating to the Certificates, which consent shall not be unreasonably
withheld), but shall not be obligated to, and the Trustee (subject to Section
9.03) shall, enter into an agreement or agreements
<PAGE>   62
                                       56

supplemental hereto for the purpose of adding any provisions to or changing in
any manner or eliminating any of the provisions of this Agreement, the
Intercreditor Agreement, the Escrow Agreement, the Deposit Agreement, the Note
Purchase Agreement or any Liquidity Facility to the extent applicable to such
Certificateholders or of modifying in any manner the rights and obligations of
such Certificateholders under this Agreement, the Intercreditor Agreement, the
Escrow Agreement, the Deposit Agreement, the Note Purchase Agreement or any
Liquidity Facility; provided, however, that no such agreement shall, without
the consent of the Certificateholder of each Outstanding Certificate affected
thereby:

                 (a)      reduce in any manner the amount of, or delay the
         timing of, any receipt by the Trustee of payments on the Equipment
         Notes held in such Trust or distributions that are required to be made
         herein on any Certificate, or change any date of payment on any
         Certificate, or change the place of payment where, or the coin or
         currency in which, any Certificate is payable, or impair the right to
         institute suit for the enforcement of any such payment or distribution
         on or after the Regular Distribution Date or Special Distribution Date
         applicable thereto; or

                 (b)      permit the disposition of any Equipment Note included
         in the Trust Property of such Trust except as permitted by this
         Agreement, or otherwise deprive such Certificateholder of the benefit
         of the ownership of the Equipment Notes in such Trust; or

                 (c)      alter the priority of distributions specified in the
         Intercreditor Agreement in a manner materially adverse to the
         interests of the Certificateholders; or

                 (d)      reduce the specified percentage of the aggregate
         Fractional Undivided Interests of such Trust that is required for any
         such supplemental agreement, or reduce such specified percentage
         required for any waiver (of compliance with certain provisions of this
         Agreement or certain defaults hereunder and their consequences)
         provided for in this Agreement; or

                 (e)      modify any of the provisions of this Section 9.02 or
         Section 6.05, except to increase any such percentage or to provide
         that certain other provisions of this Agreement cannot be modified or
         waived without the consent of the Certificateholder of each
         Certificate affected thereby; or

                 (f)      adversely affect the status of any Trust as a grantor
         trust under Subpart E, Part I of Subchapter J of Chapter 1 of Subtitle
         A of the Internal Revenue Code of 1986, as amended, for U.S. federal
         income tax purposes.
<PAGE>   63
                                       57

                 It shall not be necessary for any Direction of such
Certificateholders under this Section 9.02 to approve the particular form of
any proposed supplemental agreement, but it shall be sufficient if such
Direction shall approve the substance thereof.

                 Section 9.03.  Documents Affecting Immunity or Indemnity.  If
in the opinion of the Trustee any document required to be executed by it
pursuant to the terms of Section 9.01 or 9.02 affects any interest, right,
duty, immunity or indemnity in favor of the Trustee under this Agreement or any
Trust Supplement, the Trustee may in its discretion decline to execute such
document.

                 Section 9.04.  Execution of Supplemental Agreements.  In
executing, or accepting the additional trusts created by, any supplemental
agreement permitted by this Article or the modifications thereby of the trusts
created by this Agreement, the Trustee shall be entitled to receive, and shall
be fully protected in relying upon, an Opinion of Counsel stating that the
execution of such supplemental agreement is authorized or permitted by this
Agreement.

                 Section 9.05.  Effect of Supplemental Agreements.  Upon the
execution of any agreement supplemental to this Agreement under this Article,
this Agreement shall be modified in accordance therewith, and such supplemental
agreement shall form a part of this Agreement for all purposes; and every
Certificateholder theretofore or thereafter authenticated and delivered
hereunder shall be bound thereby to the extent applicable to such series.

                 Section 9.06.  Conformity with Trust Indenture Act.  Every
supplemental agreement executed pursuant to this Article shall conform to the
requirements of the Trust Indenture Act as then in effect.

                 Section 9.07.  Reference in Certificates to Supplemental
Agreements.  Certificates authenticated and delivered after the execution of
any supplemental agreement  pursuant to this Article may bear a notation in
form approved by the Trustee as to any matter provided for in such supplemental
agreement; and, in such case, suitable notation may be made upon Outstanding
Certificates after proper presentation and demand.


                                   ARTICLE X

                   AMENDMENTS TO INDENTURE AND NOTE DOCUMENTS

                 Section 10.01.  Amendments and Supplements to Indenture and
Other Note Documents.  In the event that the Trustee, as holder (or beneficial
owner through the Subordination Agent) of any Equipment Notes (or as a
prospective purchaser of any
<PAGE>   64
                                       58

Postponed Notes) in trust for the benefit of the Certificateholders or as
Controlling Party under an Intercreditor Agreement, receives (directly or
indirectly through the Subordination Agent) a request for a consent to any
amendment, modification, waiver or supplement under any Indenture, other Note
Document or any other related document, which request would require the consent
of Certificateholders under Section 9.02 hereof, the Trustee shall forthwith
send a notice of such proposed amendment, modification, waiver or supplement to
each Certificateholder registered on the Register as of the date of such
notice.  The Trustee shall request from the Certificateholders a Direction as
to (a) whether or not to take or refrain from taking (or direct the
Subordination Agent to take or refrain from taking) any action which a holder
of (or, with respect to Postponed Notes, a prospective purchaser of) such
Equipment Note or a Controlling Party has the option to direct, (b) whether or
not to give or execute (or direct the Subordination Agent to give or execute)
any waivers, consents, amendments, modifications or supplements as a holder of
(or, with respect to Postponed Notes, a prospective purchaser of) such
Equipment Note or as Controlling Party and (c) how to vote (or direct the
Subordination Agent to vote) any Equipment Note (or, with respect to a
Postponed Note, its commitment to acquire such Postponed Note) if a vote has
been called for with respect thereto.  Provided such a request for
Certificateholder Direction shall have been made, in directing any action or
casting any vote or giving any consent as the holder of any Equipment Note (or
in directing the Subordination Agent in any of the foregoing), (i) other than
as Controlling Party, the Trustee shall vote for or give consent to any such
action with respect to such Equipment Note (or Postponed Note) in the same
proportion as that of (A) the aggregate face amounts of all Certificates
actually voted in favor of or for giving consent to such action by such
Direction of Certificateholders to (B) the aggregate face amount of all
Outstanding Certificates and (ii) as Controlling Party, the Trustee shall vote
as directed in such Certificateholder Direction by the Certificateholders
evidencing a Fractional Undivided Interest aggregating not less than a majority
in interest in the Trust.  For purposes of the immediately preceding sentence,
a Certificate shall have been "actually voted" if the Holder of such
Certificate has delivered to the Trustee an instrument evidencing such Holder's
consent to such Direction prior to one Business Day before the Trustee directs
such action or casts such vote or gives such consent.  Notwithstanding the
foregoing, but subject to Section 6.04 and any Intercreditor Agreement, the
Trustee may, with respect to the Certificates, in its own discretion and at its
own direction, consent and notify the relevant Loan Trustee of such consent (or
direct the Subordination Agent to consent and notify the Loan Trustee of such
consent) to any amendment, modification, waiver or supplement under any related
Indenture or any other related Note Document if an Event of Default hereunder
shall have occurred and be continuing or if such amendment, modification,
waiver or supplement will not materially adversely affect the interests of the
Certificateholders.
<PAGE>   65
                                       59

                                   ARTICLE XI

                             TERMINATION OF TRUSTS

                 Section 11.01.  Termination of the Trust.  The respective
obligations and responsibilities of the Company and the Trustee shall terminate
upon the distribution to all Certificateholders and the Trustee of all amounts
required to be distributed to them pursuant to this Agreement and the
disposition of all property held as part of the Trust Property; provided,
however, that in no event shall the Trust continue beyond one hundred ten (110)
years following the date of the execution of this Agreement.

                 Notice of any termination, specifying the Distribution Date
upon which the Certificateholders may surrender their Certificates to the
Trustee for payment of the final distribution and cancellation, shall be mailed
promptly by the Trustee to Certificateholders not earlier than the 60th day and
not later than the 15th day next preceding such final Distribution Date
specifying (A) the Distribution Date upon which the proposed final payment of
the Certificates will be made upon presentation and surrender of Certificates
at the office or agency of the Trustee therein specified, (B) the amount of any
such proposed final payment, and (c) that the Record Date otherwise applicable
to such Distribution Date is not applicable, payments being made only upon
presentation and surrender of the Certificates at the office or agency of the
Trustee therein specified.  The Trustee shall give such notice to the Registrar
at the time such notice is given to Certificateholders.  Upon presentation and
surrender of the Certificates in accordance with such notice, the Trustee shall
cause to be distributed to Certificateholders such final payments.

                 In the event that all of the Certificateholders shall not
surrender their Certificates for cancellation within six months after the date
specified in the above-mentioned written notice, the Trustee shall give a
second written notice to the remaining Certificateholders to surrender their
Certificates for cancellation and receive the final distribution with respect
thereto.  No additional interest shall accrue on the Certificates after the
Distribution Date specified in the first written notice.  In the event that any
money held by the Trustee for the payment of distributions on the Certificates
shall remain unclaimed for two years (or such lesser time as the Trustee shall
be satisfied, after sixty days' notice from the Company, is one month prior to
the escheat period provided under applicable law) after the final distribution
date with respect thereto, the Trustee shall pay to each Loan Trustee the
appropriate amount of money relating to such Loan Trustee and shall give
written notice thereof to the related Owner Trustees, the Owner Participants
and the Company.
<PAGE>   66
                                       60

                                  ARTICLE XII

                            MISCELLANEOUS PROVISIONS

                 Section 12.01.  Limitation on Rights of Certificateholders.
The death or incapacity of any Certificateholder shall not operate to terminate
this Agreement or the Trust, nor entitle such Certificateholder's legal
representatives or heirs to claim an accounting or to take any action or
commence any proceeding in any court for a partition or winding up of the
Trust, nor otherwise affect the rights, obligations, and liabilities of the
parties hereto or any of them.

                 Section 12.02.  Liabilities of Certificateholders.  Neither
the existence of the Trust nor any provision in this Agreement is intended to
or shall limit the liability the Certificateholders would otherwise incur if
the Certificateholders owned Trust Property as co-owners, or incurred any
obligations of the Trust, directly rather than through the Trust.

                 Section 12.03.  Registration of Equipment Notes in Name of
Subordination Agent.  If the Trust is party to the Intercreditor Agreement, the
Trustee agrees that all Equipment Notes to be purchased by such Trust shall be
issued in the name of the Subordination Agent under the Intercreditor Agreement
or its nominee and held by such Subordination Agent in trust for the benefit of
the Certificateholders, or, if not so held, such Subordination Agent or its
nominee shall be reflected as the owner of such Equipment Notes in the register
of the issuer of such Equipment Notes.

                 Section 12.04.  Notices.  (a)  Unless otherwise specifically
provided herein, all notices required under the terms and provisions of this
Agreement shall be in English and in writing, and any such notice may be given
by United States mail, courier service or telecopy, and any such notice shall
be effective when delivered or received or, if mailed, three days after deposit
in the United States mail with proper postage for ordinary mail prepaid,

                 (i)      if to the Company:

                                  Atlas Air, Inc.
                                  538 Commons Drive
                                  Golden, CO  80401
                                  Attention:  Chief Financial Officer
                                  Facsimile:  (303) 526-5051

                 (ii)     if to the Trustee:

                                  Wilmington Trust Company
                                  One Rodney Square
<PAGE>   67
                                       61

                                  1100 N. Market Street
                                  Wilmington, DE  19890-0001
                                  Attention:  Corporate Trust Department
                                  Facsimile:  (302) 651-8882

                 (b)      The Company or the Trustee, by notice to the other,
may designate additional or different addresses for subsequent notices or
communications.

                 (c)      Any notice or communication to Certificateholders
shall be mailed by first-class mail to the addresses for Certificateholders
shown on the Register kept by the Registrar and to addresses filed with the
Trustee for Certificate Owners.  Failure so to mail a notice or communication
or any defect in such notice or communication shall not affect its sufficiency
with respect to other Certificateholders or Certificate Owners.

                 (d)      If a notice or communication is mailed in the manner
provided above within the time prescribed, it is conclusively presumed to have
been duly given, whether or not the addressee receives it.

                 (e)      If the Company mails a notice or communication to the
Certificateholders, it shall mail a copy to the Trustee and to each Paying
Agent for such series at the same time.

                 (f)      Notwithstanding the foregoing, all communications or
notices to the Trustee shall be deemed to be given only when received by a
Responsible Officer of the Trustee.

                 (g)      The Trustee shall promptly furnish the Company with a
copy of any demand, notice or written communication received by the Trustee
hereunder from any Certificateholder, Owner Trustee or Loan Trustee.

                 Section 12.05.  Governing Law.  THIS AGREEMENT HAS BEEN
DELIVERED IN THE STATE OF NEW YORK AND, TOGETHER WITH THE CERTIFICATES, SHALL
BE CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK AND THE
OBLIGATIONS, RIGHTS AND REMEDIES OF THE PARTIES HEREUNDER SHALL BE DETERMINED
IN ACCORDANCE WITH SUCH LAWS.

                 Section 12.06.  Severability of Provisions.  If any one or
more of the covenants, agreements, provisions or terms of this Agreement shall
be for any reason whatsoever held invalid, then such covenants, agreements,
provisions, or terms shall be deemed severable from the remaining covenants,
agreements, provisions or terms of this Agreement and shall in no way affect
the validity or enforceability of the other provisions of
<PAGE>   68
                                       62

this Agreement or the Trust, or of the Certificates or the rights of the
Certificateholders thereof.

                 Section 12.07.  Trust Indenture Act Controls.  Upon the
occurrence of any Registration Event, this Agreement shall become subject to
the provisions of the Trust Indenture Act and shall, to the extent applicable,
be governed by such provisions.  From and after any Registration Event, if any
provision of this Agreement limits, qualifies or conflicts with another
provision which is required to be included in this Agreement by the Trust
Indenture Act, the required provision shall control.

                 Section 12.08.  Effect of Headings and Table of Contents.  The
Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.

                 Section 12.09.  Successors and Assigns.  All covenants,
agreements, representations and warranties in this Agreement by the Trustee and
the Company shall bind and, to the extent permitted hereby, shall inure to the
benefit of and be enforceable by their respective successors and assigns,
whether so expressed or not.

                 Section 12.10.  Benefits of Agreement.  Nothing in this
Agreement or in the Certificates, express or implied, shall give to any Person,
other than the parties hereto and their successors hereunder, and the
Certificateholders, any benefit or any legal or equitable right, remedy or
claim under this Agreement.

                 Section 12.11.  Legal Holidays.  In any case where any Regular
Distribution Date or Special Distribution Date relating to any Certificate
shall not be a Business Day, then (notwithstanding any other provision of this
Agreement) payment need not be made on such date, but may be made on the next
succeeding Business Day with the same force and effect as if made on such
Regular Distribution Date or Special Distribution Date, and no interest shall
accrue during the intervening period.

                 Section 12.12.  Counterparts.  For the purpose of facilitating
the execution of this Agreement and for other purposes, this Agreement may be
executed simultaneously in any number of counterparts, each of which
counterparts shall be deemed to be an original, and all of which counterparts
shall constitute but one and the same instrument.

                 Section 12.13.  Communication by Certificateholders with Other
Certificateholders.  Certificateholders may communicate with other
Certificateholders with respect to their rights under this Agreement or the
Certificates pursuant to Section 312(b) of the Trust Indenture Act.  The
Company, the Trustee and any and all other persons benefitted by this Agreement
shall have the protection afforded by Section 312(c) of the Trust Indenture
Act.
<PAGE>   69
                                       63


                 Section 12.14.  Intention of Parties.  The parties hereto
intend that each Trust be classified for U.S.  federal income tax purposes as a
grantor trust under Subpart E, Part I of Subchapter J of the Internal Revenue
Code of 1986, as amended, and not as a trust or association taxable as a
corporation or as a partnership.  The Trustee agrees to hold all assets of each
Trust for investment purposes only.  Each Certificateholder and Investor, by
its acceptance of its Certificate or a beneficial interest therein, agrees to
treat the Trust as a grantor trust for all U.S. federal, state and local income
tax purposes.  The powers granted and obligations undertaken pursuant to this
Agreement shall be so construed so as to further such intent.
<PAGE>   70
                 IN WITNESS WHEREOF, the parties have caused this Agreement to
be duly executed by their respective officers hereunto duly authorized as of
the day and year first written above.


                                ATLAS AIR, INC.


                                By:  /s/ RICHARD H. SHUYLER
                                     -----------------------------------------
                                     Name:  Richard H. Shuyler
                                     Title: Chief Financial Officer, Sr. Vice
                                            Pres., Finance; and Corporate
                                            Treasurer


                                WILMINGTON TRUST COMPANY,
                                     as Trustee


                                By:  /s/ JAMES P. LAWLER
                                     -----------------------------------------
                                     Name:  JAMES P. LAWLER
                                     Title: Vice President