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

i

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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[Escrow and Paying Agent Agreement (Class A)]

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