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                                                                    EXHIBIT 4.21

              AMERICAN AIRLINES, INC. PASS THROUGH TRUST AGREEMENT
                                  March 21,2002

INSTRUMENT OF RESIGNATION, APPOINTMENT AND ACCEPTANCE, dated as of June 30, 2003
among U.S. Bank National Association ("Resigning Trustee"), American Airlines,
Inc., a Delaware corporation (the "Company"), and U.S. Bank Trust National
Association (the "Successor Trustee").

                                    RECITALS

         A.       The Resigning Trustee acts as successor Trustee under the Pass
                  Through Trust Agreement, dated as of March 21, 2002 (the
                  "Basic Agreement"), as supplemented by those certain separate
                  Trust Supplements as described on Schedule 1 hereto (the
                  "Trust Supplements"), between the Company and the Resigning
                  Trustee. Capitalized terms used herein and not defined shall
                  have the meanings ascribed to them in or by reference in the
                  Basic Agreement and the Trust Supplements.

         B.       The Resigning Trustee wishes to resign as Trustee under the
                  Basic Agreement and each of the Trust Supplements; the Company
                  wishes to appoint the Successor Trustee to succeed the
                  Resigning Trustee as Trustee under the Basic Agreement and the
                  Trust Supplements and the Successor Trustee wishes to accept
                  such appointments.

         NOW, THEREFORE, the Company, the Resigning Trustee and the Successor
Trustee agree as follows:

                                   ARTICLE ONE
                              THE RESIGNING TRUSTEE

Section 101. Pursuant to Section 7.09(b) of the Basic Agreement, the Resigning
Trustee hereby resigns as Trustee under the Basic Agreement, the Trust
Supplements, the Intercreditor Agreements, the Participation Agreements (as
described in the Trust Supplements) and all such other related transaction
documents or instruments to which the Resigning Trustee is a party
(collectively, the "Operative Documents"). The Resigning Trustee agrees to
execute and deliver such agreements and other instruments as may be necessary or
desirable to effectuate the succession of the Successor Trustee as Trustee under
the Basic Agreement, the Trust Supplements and the other Operative Documents.

Section 102. The Resigning Trustee hereby represents and warrants to the
Successor Trustee that:

         (a)      To the knowledge of the Resigning Trustee, no Events of
                  Default have occurred or are continuing under the Trust
                  Supplements or the other Operative Documents.

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         (b)      There is no action, suit or proceeding pending or, to the best
                  of the knowledge of the Responsible Officers of the Resigning
                  Trustee assigned to its Corporate Trust Department, threatened
                  against the Resigning Trustee before any court or governmental
                  authority arising out of any action or omission by the
                  Resigning Trustee as Trustee under the Basic Agreement or the
                  other Operative Documents.

         (c)      It assumes continued responsibility for its actions or
                  omissions during its term as Trustee under the Basic
                  Agreement, each Trust Supplement and the other Operative
                  Documents.

                                   ARTICLE TWO
                                   THE COMPANY

Section 201. The Company hereby (a) appoints the Successor Trustee as Trustee
under the Basic Agreement and each Trust Supplement.

Section 202. The Company hereby confirms to the Successor Trustee all the
rights, trusts and powers under the Operative Documents hereby assigned,
transferred, delivered and confirmed to the Successor Trustee.

                                  ARTICLE THREE
                              THE SUCCESSOR TRUSTEE

Section 301. The Successor Trustee hereby represents and warrants to the Company
and the Secretary that the Successor Trustee is qualified and eligible under the
provisions of Article VII of the Basic Agreement.

Section 302. The Successor Trustee hereby accepts its appointment as Trustee
under the Basic Agreement and the Trust Supplements and shall hereby be vested
with all the rights, powers, trusts and duties of the Trustee under the Basic
Agreement, the Trust Supplements and the other Operative Documents. The
Successor Trustee agrees to execute and deliver such agreements and other
instruments as may be necessary or desirable to effectuate the succession of the
Successor Trustee as Trustee under the Basic Agreement, the Trust Supplements
and the other Operative Documents.

                                  ARTICLE FOUR
                                  MISCELLANEOUS

Section 401. This Instrument and the resignation, appointment and acceptance
effected hereby shall be effective as of the opening of business on the date
first above written upon the execution and delivery hereof by each of the
parties hereto.

Section 402. The Instrument shall be governed by and constructed in accordance
with the laws of the jurisdiction which govern the Basic Agreement and the Trust
Supplements and their construction.

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Section 403. This instrument may be executed in any number of counterparts each
of which shall be an original, but such counterparts shall together constitute
but one and the same instrument.

               [SIGNATURES OF THE PARTIES APPEAR ON THE NEXT PAGE]

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         IN WITNESS WHEREOF, the parties hereby have caused this Instrument of
Resignation, Appointment and Acceptance to be executed by their duly authorized
officers all as of the day and year first above written.

                                          AMERICAN AIRLINES, INC.
                                          (the "Company")

                                          By: /s/ Michael P. Thomas
                                             -----------------------------------
                                                  Michael P. Thomas
                                                  Managing Director,
                                                  Corporate Finance and Banking

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                                          U.S. BANK NATIONAL ASSOCIATION
                                          (the "Resigning Trustee")

                                          By: /s/ Alison D.B. Nadeau
                                             -----------------------------------
                                          Name: Alison D.B. Nadeau
                                          Title: Vice President

                                          U.S. BANK TRUST NATIONAL ASSOCIATION
                                          (the "Successor Trustee")

                                          By: /s/ Alison D.B. Nadeau
                                             -----------------------------------
                                          Name: Alison D.B. Nadeau
                                          Title: Vice President

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                                   SCHEDULE 1

Trust Supplement No. 2002-1G, dated as of September 24, 2002, between the
Company and the Resigning Trustee in respect of American Airlines Pass Through
Trust 2002-1G.

Trust Supplement No. 2002-1C, dated as of September 24, 2002, between the
Company and the Resigning Trustee in respect of American Airlines Pass Through
Trust 2002-1C.

Trust Supplement No. 2002-1D, dated as of September 24, 2002, between the
Company and the Resigning Trustee in respect of American Airlines Pass Through
Trust 2002-1D.