Exhibit 10.11 United Air Lines, Inc. P.0. Box 66100 Chicago, Illinois 60666 Subject: Letter Agreement No. 6-1162-MDH-077 Purchase Agreement No. 1663 [*CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] Reference is made to Purchase Agreement No. 1663 dated December 18, 1990 (the Purchase Agreement) between The Boeing Company (Boeing), and United Air Lines, Inc. (Buyer), relating to the sale by Boeing and the Purchase by Buyer of thirty-four (34) Model 777-222 aircraft (hereinafter referred to as the Aircraft). This Letter Agreement will become part of the Purchase Agreement and will evidence our further agreement with respect to the matters set forth below. All terms used herein and in the Purchase Agreement, and not defined herein, shall have the same meaning as in the Purchase Agreement. [*CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] United Air Lines Inc. 6-1162-MDH-077 Page 2 [*CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] United Air Lines Inc. 6-1162-MDH-077 Page 3 [*CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] If the foregoing correctly sets forth your understanding of our agreement with respect to the matters treated above, please indicate your acceptance and approval below. Very truly yours, THE BOEING COMPANY By /s/ M. O. Hunt -------------- Its Attorney in Fact ---------------- ACCEPTED AND AGREED TO this Date: April 6, 1996 UNITED AIR LINES, INC. By /s/ Frederic Brace ------------------ Its Vice President and Controller -----------------------------