Exhibit 21

United Continental Holdings, Inc. and United Airlines, Inc. Subsidiaries

(as of February 22, 2018)

Entity	Jurisdiction of Incorporation
United Continental Holdings, Inc.	Delaware
Wholly-owned subsidiaries*:
United Airlines, Inc.	Delaware
•  Air Wis Services, Inc.	Wisconsin
•  Air Wisconsin, Inc.	Delaware
•  Domicile Management Services, Inc. **	Delaware
•  Air Micronesia, LLC.	Delaware
•  CAL Cargo, S.A. de C.V.**	Mexico
•  CALFINCO Inc.	Delaware
•  Century Casualty Company	Vermont
•  Continental Airlines de Mexico, S.A.**	Mexico
•  Continental Airlines Domain Name Limited	England
•  Continental Airlines Finance Trust II	Delaware
•  Continental Airlines Fuel Purchasing Group, LLC	Delaware
•  Continental Airlines, Inc. Supplemental Retirement
Plan for Pilots Trust Agreement	Delaware
•  Continental Airlines Purchasing Holdings LLC	Delaware
•  Continental Airlines Purchasing Services LLC**	Delaware
•  Continental Express, Inc.	Delaware
•  Covia LLC	Delaware
•  Mileage Plus Holdings, LLC	Delaware
•  MPH I, Inc.	Delaware
•  Mileage Plus Marketing, Inc.	Delaware
•  Mileage Plus, Inc.	Delaware
•  Presidents Club of Guam, Inc.	Delaware
•  UABSPL Holdings, Inc.	Delaware
•  UAL Benefits Management, Inc.**	Delaware
•  United Atlantic LP**	Delaware
•  United Atlantic Services C.V.**	Delaware
•  United Atlantic Corporate LLC	Delaware
•  United Atlantic Corporate Center C.V.**	Netherlands
•  United Atlantic Finance	Cayman Islands
•  United Atlantic B.V.	Netherlands
•  United Atlantic Services LLC	Delaware
•  United Aviation Fuels Corporation	Delaware

•  United Airlines Business Private Services Limited**	India
•  United Ground Express, Inc.	Delaware
•  United Travel Services, LLC	Delaware
•  United Vacations, Inc.	Delaware

* Subsidiaries of United Continental Holdings, Inc. are wholly owned unless otherwise indicated

** Domicile Management Services Inc. is 99.9% owned by Air Wis Services, Inc. and 0.1% owned by United Airlines, Inc. CAL Cargo, S.A. de C.V. is 99.99% owned by United Airlines, Inc. and .01% owned by CALFINCO Inc. Continental Airlines de Mexico, S.A. is 99.9997% owned by United Airlines, Inc. and .0003% owned by private entities. Continental Airlines Purchasing Services LLC is 99% owned by Continental Airlines Purchasing Holdings LLC and 1% owned by United Airlines, Inc. UAL Benefits Management, Inc. has 100% of its Class A Common Stock owned by United Airlines, Inc. and 100% of its Class B Common Stock owned by Health Care Services Corporation. United Atlantic LP is 99.9% owned by United Airlines, Inc. and 0.1% owned by United Atlantic Services LLC. United Atlantic Services C.V. is 99.9% owned by United Atlantic LP and 0.1% owned by United Atlantic Services LLC. United Atlantic Corporate Center C.V. is 99.9% owned by United Atlantic Services C.V. and 0.1% owned by United Atlantic Corporate LLC. United Airlines Business Private Services Limited is 99.99% owned by United Airlines, Inc. and 0.01% owned by UABSPL Holdings, Inc. on behalf of United Airlines, Inc.