United Airlines 10-Q 2011 Q2 Quarterly report

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 period ended June 30, 2011 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 25, 2011

/s/ Jeffery A. Smisek

Jeffery A. Smisek

President and Chief Executive Officer

/s/ Zane C. Rowe

Zane C. Rowe

Executive Vice President and

Chief Financial Officer

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