Supplemental Agreement No. 18 to Purchase Agreement No. 03776 between The Boeing Company and United Airlines, Inc. dated as of September 8, 2021

THIS SUPPLEMENTAL AGREEMENT, entered into as of September 8, 2021, by and between THE BOEING COMPANY (Boeing) and UNITED AIRLINES, INC. (Customer) (SA-18);

WHEREAS, the parties hereto entered into Purchase Agreement No. 3776 dated July 12, 2012, as amended and supplemented (Purchase Agreement), relating to the purchase and sale of Boeing model 737 MAX aircraft (Aircraft). This Supplemental Agreement is an amendment to the Purchase Agreement; and

WHEREAS, Customer and Boeing agree to *** 737-*** Aircraft as follows:

WHEREAS, Customer and Boeing agree to revise certain ***

NOW THEREFORE, in consideration of the mutual covenants herein contained, the parties agree to amend the Purchase Agreement as follows:

The “Table of Contents” is deleted in its entirety and replaced with the attached “Table of Contents” (identified by “SA-18”).

Table 1.1 titled “*** 737-*** Aircraft Delivery, Description, Price and ***” is deleted in its entirety and replaced with the attached similarly titled Table 1 (identified by “SA-18”) to reflect the *** 737-*** aircraft.

Letter Agreement No. UAL-PA-03776-LA-1208157R3 is deleted in its entirety and replaced with Letter Agreement No. UAL-PA-03776-LA-1208157R4 titled “***” (identified by “SA-18”) to revise the *** for the 737-*** aircraft.

4.1.The following letter agreements are deemed to revise references as follows:

4.2.The following references to “Table 1” in the Purchase Agreement and the associated exhibits, supplemental exhibits, and letter agreements to the Purchase Agreement are now deemed to be replaced per Figure 1 as follows:

4.3.If Boeing or Customer determines that references described in Section 4 of this Supplemental Agreement No. 18 should be further amended, then Boeing and Customer will work together for a mutually agreeable solution.

Subject:    ***

Reference:    Purchase Agreement No. PA-03776 (Purchase Agreement) between The Boeing Company (Boeing) and United Airlines, Inc. (Customer) relating to Model 737 MAX aircraft (Aircraft)

This letter agreement (Letter Agreement) amends and supplements the Purchase Agreement. This Letter Agreement supersedes and replaces in its entirety Letter Agreement UCH-PA-03776-LA-1208157R3.

All terms used herein and in this Letter Agreement, and not defined herein, will have the same meaning as in the Purchase Agreement.

Subject to the terms, provisions, and conditions described herein, *** any Aircraft, as of the effective date (Effective Date) of the ***.

Boeing *** to Customer, at a charge as described in paragraph 3 below, *** an Aircraft *** for the respective model type. The Effective Date of such *** shall be the date that Boeing provides *** to Customer, unless otherwise mutually agreed to. *** for the applicable Aircraft ***. Boeing will use its best reasonable efforts to provide *** not later than *** after receipt of Customer's written request.

At the time of delivery of each Aircraft, or *** after delivery of an Aircraft, *** as requested by Customer. Such *** shall be ***, identifying the Aircraft Manufacturer's Serial Number (MSN), the delivery date and the Effective Date of the *** The *** shall also indicate the ***

If Customer elects ***:

***

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. UAL-PA-03776-LA-1208234.