Exhibit 10.24

6-1162-IRS-0183

United Air Lines, Inc.

P.O. Box 66100

Chicago, IL
60601-0100



|           |  |                                                                                                                                                                     
|---------- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Subject:   |  | [CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] to the Purchase Agreement                        
|           | 
|Reference: |  | Purchase Agreement No. 3427 (Purchase Agreement) between The Boeing Company (Boeing) and United Air Lines, Inc. (Customer) relating to Model 787 aircraft
(Aircraft)

This letter agreement (Letter Agreement) is entered into on the date below, and amends and supplements the Purchase
Agreement. All capitalized terms used herein but not otherwise defined in this Letter Agreement have the same meaning as in the Purchase Agreement.



|1. | Purchase Agreement.
|-- | -------------------

[CONFIDENTIAL
MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT]



P.A. No. 3427

[CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] to the Purchase Agreement

BOEING / UNITED PROPRIETARY



---

United Air Lines, Inc.

6-1162-IRS-0183



|2. | [CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT]
|-- | ------------------------------------------------------------------------------------------------------------------



|3. | [CONFIDENTIAL MATERIAL FROM SECTION 3 IN PAGES 6 TO 16 OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT]
|-- | --------------------------------------------------------------------------------------------------------------------------------------------------



|4. | Assignment.
|-- | -----------

The rights
and obligations described in this Letter Agreement are provided to Customer in consideration of Customer becoming the operator of the Aircraft and can only be assigned, in whole or in part, pursuant to Article 9 of the AGTA as amended by Letter
Agreement No. 6-1162-IRS-0184.



P.A. No. 3427

[CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] to the Purchase Agreement

BOEING / UNITED PROPRIETARY



---

United Air Lines, Inc.

6-1162-IRS-0183



|5. | Confidential Treatment.
|-- | -----------------------

Customer and Boeing understand that certain commercial and financial information contained in this Letter Agreement are considered by
Boeing and Customer as confidential and are subject to the terms and conditions set forth in Letter Agreement No. 6-1162-IRS-0182.



|                            |  |                 
|--------------------------- |  | ----------------
|Very truly yours,          
|                           
|THE BOEING COMPANY         
|                            | 
|By                          |  | /s/ Nobuko Wiles
|                            | 
|Its                         |  | Attorney-In-Fact
|                           
|ACCEPTED AND AGREED TO this
|                           
|Date: February 19, 2010    
|                           
|UNITED AIR LINES, INC.     

|    |  |                                                     
|--- |  | ----------------------------------------------------
|    | 
|By  |  | /s/ Kathryn A. Mikells                              
|    | 
|Its |  | Executive Vice President and Chief Financial Officer



P.A. No. 3427

[CONFIDENTIAL MATERIAL OMITTED AND FILED SEPARATELY WITH THE SEC PURSUANT TO A REQUEST FOR CONFIDENTIAL TREATMENT] to the Purchase Agreement

BOEING / UNITED PROPRIETARY