Exhibit 31.1

Certification of the Principal Executive Officer
Pursuant to 15 U.S.C. 78m(a) or 78o(d)
(Section 302 of the Sarbanes-Oxley Act of 2002)

I, Glenn F. Tilton, the Chairman, President and Chief Executive Officer of UAL Corporation (the "Company"), certify that:

(1)     I have reviewed this quarterly report on Form 10-Q for the period ended March 31, 2005 of the
         Company;   (2)     Based on my knowledge, this report does not contain any untrue statement of a material fact or omit
          to state a material fact necessary to make the statements made, in light of the circumstances under
          which such statements were made, not misleading with respect to the period covered by this report;   (3)     Based on my knowledge, the financial statements, and other financial information included in this
          report, fairly present in all material respects the financial condition, results of operations and cash
          flows of the Company as of, and for, the periods presented in this report;   (4)     The Company's other certifying officer and I are responsible for establishing and maintaining disclosure
          controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal
          control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the
          Company and have:
  (a)     Designed such disclosure controls and procedures, or caused such disclosure controls
         and procedures to be designed under our supervision, to ensure that material information
         relating to the Company, including its consolidated subsidiaries, is made known to us by
         others within those entities, particularly during the period in which this report is being
         prepared;   (b)     Designed such internal control over financial reporting, or caused such internal control
         over financial reporting to be designed under our supervision, to provide reasonable
         assurance regarding the reliability of financial reporting and the preparation of financial
         statements for external purposes in accordance with generally accepted accounting
         principles;   (c)     Evaluated the effectiveness of the Company's disclosure controls and procedures and
         presented in this report our conclusions about the effectiveness of the disclosure controls
         and procedures, as of the end of the period covered by this report based on such
         evaluation; and   (d)     Disclosed in this report any change in the Company's internal control over financial
         reporting that occurred during the Company's most recent fiscal quarter that has
         materially affected, or is reasonably likely to materially affect, the Company's internal
         control over financial reporting; and
  (5)     The Company's other certifying officer and I have disclosed, based on our most recent evaluation of
          internal control over financial reporting, to the Company's auditors and the audit committee of
          Company's board of directors (or persons performing the equivalent functions):
  (a)     All significant deficiencies and material weaknesses in the design or operation of internal
         control over financial reporting which are reasonably likely to adversely affect the
         Company's ability to record, process, summarize and report financial information; and   (b)     Any fraud, whether or not material, that involves management or other employees who
         have a significant role in the Company's internal control over financial reporting.   /s/ Glenn F. Tilton__________
Glenn F. Tilton
UAL Corporation
Chairman, President and Chief Executive Officer
May 11, 2005