Exhibit 32.1

Certification of United Continental Holdings, Inc.

Pursuant to 18 U.S.C. 1350

(Section 906 of the Sarbanes-Oxley Act of 2002)

Each undersigned officer certifies that to the best of his knowledge based on a review of the quarterly report on Form 10-Q for the quarterly period ended June 30, 2018 of United Continental Holdings, Inc. (the "Report"):

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of United Continental Holdings, Inc.

Date: July 18, 2018

/s/ Oscar Munoz

Oscar Munoz

Chief Executive Officer

/s/ Gerald Laderman

Gerald Laderman

Senior Vice President Finance and acting Chief Financial Officer