ESCROW AND PAYING AGENT AGREEMENT (CLASS A)

Exhibit 4.11

ESCROW AND

PAYING AGENT AGREEMENT (CLASS A)

dated as of October 13, 2009

among

WILMINGTON TRUST COMPANY

as Escrow Agent

MORGAN STANLEY & CO. INCORPORATED,

J.P. MORGAN SECURITIES INC.

and

GOLDMAN, SACHS & CO.

as Underwriters

WILMINGTON TRUST COMPANY ,

not in its individual capacity,

but solely as Pass Through Trustee

for and on behalf of

United Air Lines Pass Through Trust 2009-1A-O

as Pass Through Trustee

and

WILMINGTON TRUST COMPANY

as Paying Agent

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ESCROW AND PAYING AGENT AGREEMENT (CLASS A)

ESCROW AND PAYING AGENT AGREEMENT (Class A) dated as of October 13, 2009 (as amended, modified or supplemented from time to time, this “ Agreement ”) among WILMINGTON TRUST COMPANY , a Delaware banking corporation, as Escrow Agent (in such capacity, together with its successors in such capacity, the “ Escrow Agent ”); MORGAN STANLEY & CO. INCORPORATED , J.P. MORGAN SECURITIES INC. and GOLDMAN, SACHS & CO. , as Underwriters (the “ Underwriters ” and together with their respective transferees and assigns as registered owners of the Certificates, the “ Investors ”) under the Underwriting Agreement referred to below; WILMINGTON TRUST COMPANY , a Delaware banking corporation, not in its individual capacity except as otherwise expressly provided herein, but solely as trustee (in such capacity, together with its successors in such capacity, the “ Pass Through Trustee ”) under the Pass Through Trust Agreement referred to below; and WILMINGTON TRUST COMPANY , a Delaware banking corporation, as paying agent hereunder (in such capacity, together with its successors in such capacity, the “ Paying Agent ”).

W I T N E S S E T H :

WHEREAS , United Air Lines, Inc. (“ United ”) and the Pass Through Trustee have entered into a Trust Supplement, dated as of October 13, 2009 (the “ Trust Supplement ”) to the Pass Through Trust Agreement, dated as of June 26, 2007 (together, as amended, modified or supplemented from time to time in accordance with the terms thereof, the “ Pass Through Trust Agreement ”) relating to United Air Lines Pass Through Trust 2009-1A-O (the “ Pass Through Trust ”) pursuant to which the United Air Lines Pass Through Trust, Series 2009-1A-O Certificates referred to therein (the “ Certificates ”) are being issued (the date of such issuance, the “ Issuance Date ”);

WHEREAS , United and the Underwriters have entered into an Underwriting Agreement dated October 5, 2009 (as amended, modified or supplemented from time to time in accordance with the terms thereof, the “ Underwriting Agreement ”) pursuant to which the Pass Through Trustee will issue and sell the Certificates to the Underwriters (the net proceeds of such sale being herein referred to as the “ Net Proceeds ”);

WHEREAS , United, the Pass Through Trustee and certain other persons concurrently herewith are entering into the Note Purchase Agreement, dated as of the date hereof (the “ Note Purchase Agreement ”), pursuant to which the Pass Through Trustee has agreed to acquire from time to time on or prior to the Deposit Period Termination Date (as defined in the Note Purchase Agreement) equipment notes (the “ Equipment Notes ”) issued to finance certain aircraft currently owned by United utilizing a portion of the Net Proceeds;

WHEREAS , the Underwriters and the Pass Through Trustee intend that the Net Proceeds be held in escrow by the Escrow Agent on behalf of the Investors, subject to withdrawal upon request by the Pass Through Trustee and satisfaction of the conditions set forth in the Note Purchase Agreement for the purpose of purchasing Equipment Notes, and that pending such withdrawal the Net Proceeds be deposited on behalf of the Escrow Agent with JPMorgan Chase Bank, N.A., a national banking association, as Depositary (the “ Depositary ” which shall also be deemed to refer to any Replacement Depositary (as defined in the Note

[Escrow and Paying Agent Agreement (Class A)]

Purchase Agreement) from and after the date on which the Deposits are transferred to such Replacement Depositary) under the Deposit Agreement, dated as of the date hereof between the Depositary and the Escrow Agent relating to the Pass Through Trust (as amended, modified, supplemented or replaced from time to time in accordance with the terms thereof, the “ Deposit Agreement ” which shall also be deemed to refer to any Replacement Deposit Agreement (as defined in the Note Purchase Agreement) to which the Escrow Agent becomes a party pursuant to Section 1.02(a) hereof from and after the transfer of the Deposits from the Depositary to the Replacement Depositary) pursuant to which, among other things, the Depositary will pay interest for distribution to the Investors and establish accounts from which the Escrow Agent shall make withdrawals upon request of and proper certification by the Pass Through Trustee;

WHEREAS , the Escrow Agent wishes to appoint the Paying Agent to pay amounts required to be distributed to the Investors in accordance with this Agreement; and

WHEREAS , capitalized terms used but not defined herein shall have the meanings ascribed to such terms in the Pass Through Trust Agreement.

NOW, THEREFORE , in consideration of the obligations contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto hereby agree as follows:

Section 1.        Escrow Agent .

1.01.       Appointment of Escrow Agent .  Each of the Underwriters, for and on behalf of each of the Investors, hereby irrevocably appoints, authorizes and directs the Escrow Agent to act as escrow agent and fiduciary hereunder and under the Deposit Agreement for such specific purposes and with such powers as are specifically delegated to the Escrow Agent by the terms of this Agreement, together with such other powers as are reasonably incidental thereto. Any and all money received and held by the Escrow Agent under this Agreement or the Deposit Agreement shall be held in escrow by the Escrow Agent in accordance with the terms of this Agreement. This Agreement is irrevocable and the Investors’ rights with respect to any monies received and held in escrow by the Escrow Agent under this Agreement or the Deposit Agreement shall only be as provided under the terms and conditions of this Agreement and the Deposit Agreement. The Escrow Agent (which term as used in this sentence shall include reference to its affiliates and its own and its affiliates’ officers, directors, employees and agents): (a) shall have no duties or responsibilities except those expressly set forth in this Agreement; (b) shall not be responsible to the Pass Through Trustee or the Investors for any recitals, statements, representations or warranties of any person other than itself contained in this Agreement or the Deposit Agreement or for the failure by the Pass Through Trustee, the Investors or any other person or entity (other than the Escrow Agent) to perform any of its obligations hereunder (whether or not the Escrow Agent shall have any knowledge thereof); and (c) shall not be responsible for any action taken or omitted to be taken by it hereunder or provided for herein or in connection herewith, except for its own willful misconduct or gross negligence (or simple negligence in connection with the handling of funds actually received by it in accordance with the terms of this Agreement) or breach of its obligations hereunder.

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1.02.       Instruction; Etc.   The Underwriters, for and on behalf of each of the Investors, hereby irrevocably instruct the Escrow Agent, and the Escrow Agent agrees, (a) to enter into the Deposit Agreement and, if requested by the Company pursuant to Section 4(a)(iii) of the Note Purchase Agreement, to enter into a Replacement Deposit Agreement with the Replacement Depositary specified by the Company, (b) to appoint the Paying Agent as provided in this Agreement, (c) upon receipt at any time and from time to time prior to the Termination Date (as defined below) of a certificate substantially in the form of Exhibit B hereto (a “ Withdrawal Certificate ”) executed by the Pass Through Trustee, together with an attached Notice of Financing Withdrawal in substantially the form of Exhibit A to the Deposit Agreement duly completed by the Pass Through Trustee (the “ Applicable Notice of Financing Withdrawal ” and the withdrawal to which it relates, a “ Financing Withdrawal ”), immediately to execute the Applicable Notice of Financing Withdrawal as Escrow Agent and transmit it to the Depositary by facsimile transmission in accordance with the Deposit Agreement; provided that, upon the request of the Pass Through Trustee after such transmission, the Escrow Agent shall cancel such Applicable Notice of Financing Withdrawal, (d) upon receipt of a Withdrawal Certificate executed by the Pass Through Trustee, together with an attached Notice of Replacement Withdrawal in substantially the form of Exhibit C to the Deposit Agreement duly completed by the Pass Through Trustee, to (X) give such Notice of Replacement Withdrawal to the Depositary requesting a withdrawal, on the date specified in such notice, which shall not be less than Five Business Days after such notice is given (the “ Replacement Withdrawal Date ”), of all Deposits then held by the Depositary together with all accrued and unpaid interest on such Deposits to but excluding the Replacement Withdrawal Date, and (Y) direct the Depositary to transfer such Deposits and accrued interest on behalf of the Escrow Agent to the Replacement Depositary in accordance with the Replacement Deposit Agreement, and (e) if there are any undrawn Deposits (as defined in the Deposit Agreement) on the “ Termination Date ”, which shall mean the earlier of (i) the Deposit Period Termination Date (as defined in the Note Purchase Agreement) and (ii) the day on which the Escrow Agent receives notice from the Pass Through Trustee that the Pass Through Trustee’s obligation to purchase Equipment Notes under the Note Purchase Agreement has terminated, to immediately give notice to the Depositary (with a copy to the Paying Agent) substantially in the form of Exhibit B to the Deposit Agreement requesting a withdrawal of all of the remaining Deposits, together with accrued and unpaid interest on such Deposits to the date of withdrawal, on the 25th day after the date that such notice of withdrawal is given to the Depositary (or, if not a Business Day, on the next succeeding Business Day) (a “ Final Withdrawal ”), provided that if the day scheduled for the Final Withdrawal in accordance with the foregoing is within 10 days before or after a Regular Distribution Date, then the Escrow Agent shall request that such requested Final Withdrawal be made on such Regular Distribution Date (the date of such requested withdrawal, the “ Final Withdrawal Date ”). If for any reason the Escrow Agent shall have failed to give the Final Withdrawal notice to the Depositary on or before January 14, 2010, and there are unwithdrawn Deposits on such date, the Final Withdrawal Date shall be deemed to be January 21, 2010.

1.03.       Initial Escrow Amount; Issuance of Escrow Receipts .  The Escrow Agent hereby directs the Underwriters to, and the Underwriters hereby acknowledge that on the date hereof they shall, irrevocably deliver to the Depositary on behalf of the Escrow Agent, an amount in U.S. dollars (“ Dollars ”) and immediately available funds equal to $659,107,000 for deposit on behalf of the Escrow Agent with the Depositary in accordance with Section 2.1 of the Deposit Agreement. The Underwriters hereby instruct the Escrow Agent, upon receipt of such sum from the Underwriters, to confirm such receipt by executing and

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[Escrow and Paying Agent Agreement (Class A)]

delivering to the Pass Through Trustee an Escrow Receipt in the form of Exhibit A hereto (an “ Escrow Receipt ”), (a) to be affixed by the Pass Through Trustee to each Certificate and (b) to evidence the same percentage interest (the “ Escrow Interest ”) in the Account Amounts (as defined below) as the Fractional Undivided Interest in the Pass Through Trust evidenced by the Certificate to which it is to be affixed. The Escrow Agent shall provide to the Pass Through Trustee for attachment to each Certificate newly issued under and in accordance with the Pass Through Trust Agreement an executed Escrow Receipt as the Pass Through Trustee may from time to time request of the Escrow Agent. Each Escrow Receipt shall be registered by the Escrow Agent in a register (the “ Register ”) maintained by the Escrow Agent in the name of the same holder that is the holder of the Certificate to which it is attached and may not thereafter be detached from such Certificate to which it is to be affixed prior to the distribution of the Final Withdrawal (the “ Final Distribution ”). After the Final Distribution, no additional Escrow Receipts shall be issued and the Pass Through Trustee shall request the return to the Escrow Agent for cancellation of all outstanding Escrow Receipts.

1.04.       Payments to Receiptholders .  All payments and distributions made to holders of an Escrow Receipt (collectively “ Receiptholders ”) in respect of the Escrow Receipt shall be made only from amounts deposited in the Paying Agent Account (as defined below) (“ Account Amounts ”). Each Receiptholder, by its acceptance of an Escrow Receipt, agrees that (a) it will look solely to the Account Amounts for any payment or distribution due to such Receiptholder pursuant to the terms of the Escrow Receipt and this Agreement (subject to Section 15 hereof) and (b) it will have no recourse to United, the Pass Through Trustee, the Paying Agent, the Escrow Agent or Wilmington Trust Company, except as expressly provided herein or in the Pass Through Trust Agreement. No Receiptholder shall have any right to vote or in any manner otherwise control the operation and management of the Paying Agent Account or the obligations of the parties hereto, nor shall anything set forth herein, or contained in the terms of the Escrow Receipt, be construed so as to constitute the Receiptholders from time to time as partners or members of an association.

1.05.       Mutilated, Destroyed, Lost or Stolen Escrow Receipt .  If (a) any mutilated Escrow Receipt is surrendered to the Escrow Agent or the Escrow Agent receives evidence to its satisfaction of the destruction, loss or theft of any Escrow Receipt and (b) there is delivered to the Escrow Agent and the Pass Through Trustee such security, indemnity or bond, as may be required by them to hold each of them harmless, then, absent notice to the Escrow Agent or the Pass Through Trustee that such destroyed, lost or stolen Escrow Receipt 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 Escrow Agent shall execute, authenticate and deliver, in exchange for or in lieu of any such mutilated, destroyed, lost or stolen Escrow Receipt, a new Escrow Receipt or Escrow Receipts and of like Escrow Interest in the Account Amounts and bearing a number not contemporaneously outstanding.

In connection with the issuance of any new Escrow Receipt under this Section 1.05, the Escrow Agent 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 Pass Through Trustee and the Escrow Agent) connected therewith.

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[Escrow and Paying Agent Agreement (Class A)]

Any duplicate Escrow Receipt issued pursuant to this Section 1.05 shall constitute conclusive evidence of the appropriate Escrow Interest in the Account Amounts, as if originally issued, whether or not the lost, stolen or destroyed Escrow Receipt 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 Escrow Receipts.

1.06.       Additional Escrow Amounts .  On the date of any Financing Withdrawal, the Pass Through Trustee may re-deposit with the Depositary some or all of the amounts so withdrawn in accordance with Section 2.4 of the Deposit Agreement.

1.07.       Resignation or Removal of Escrow Agent .  Subject to the appointment and acceptance of a successor Escrow Agent as provided below, the Escrow Agent may resign at any time by giving 30 days’ prior written notice thereof to the Investors, but may not otherwise be removed except for cause by the written consent of the Investors with respect to Investors representing Escrow Interests aggregating not less than a majority in interest in the Account Amounts (an “ Action of Investors ”). Upon any such resignation or removal, the Investors, by an Action of Investors, shall have the right to appoint a successor Escrow Agent. If no successor Escrow Agent shall have been so appointed and shall have accepted such appointment within 30 days after the retiring Escrow Agent’s giving of notice of resignation or the removal of the retiring Escrow Agent, then the retiring Escrow Agent may appoint a successor Escrow Agent. Any successor Escrow Agent shall be a bank which has an office in the United States with a combined capital and surplus of at least $100,000,000. Upon the acceptance of any appointment as Escrow Agent hereunder by a successor Escrow Agent, such successor Escrow Agent shall enter into such documents as the Pass Through Trustee shall require and shall thereupon succeed to and become vested with all the rights, powers, privileges and duties of the retiring Escrow Agent, and the retiring Escrow Agent shall be discharged from its duties and obligations hereunder. No resignation or removal of the Escrow Agent shall be effective unless a written confirmation shall have been obtained from each of Moody’s Investors Service, Inc. and Standard & Poor’s Ratings Services, a Standard & Poor’s Financial Services LLC business, that the replacement of the Escrow Agent with the successor Escrow Agent will not result in (a) a reduction of the rating for the Certificates below the then current rating for the Certificates or (b) a withdrawal or suspension of the rating of the Certificates.

1.08.       Persons Deemed Owners .  Prior to due presentment of a Certificate for registration of transfer