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$150,000,000

Senior Convertible Notes due 2023

     This document supplements the prospectus of Alaska Air Group, Inc. dated October 7, 2003, the prospectus supplement dated November 4, 2003, the prospectus supplement dated November 17, 2003, the prospectus supplement dated January 13, 2004 and the prospectus supplement dated January 28, 2004 relating to the notes issued in a private placement in March 2003 and the common stock issuable upon conversion of the notes. This prospectus supplement updates the prospectus dated October 7, 2003, as supplemented to date, with the attached Current Report on Form 8-K of Alaska Air Group, Inc. dated February 26, 2004.

     This prospectus supplement is incorporated by reference into, and should be read in conjunction with, the prospectus dated October 7, 2003, the prospectus supplement dated November 4, 2003, the prospectus supplement dated November 17, 2003 the prospectus supplement dated January 13, 2004 and the prospectus supplement dated January 28, 2004. This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the prospectus dated October 7, 2003, the prospectus supplement dated November 4, 2003, the prospectus supplement dated November 17, 2003 the prospectus supplement dated January 13, 2004 and the prospectus supplement dated January 28, 2004.

     We have not applied for listing of the notes on any securities exchange or for quotation through any automated quotation system. The notes were offered to qualified institutional buyers as defined in, and in reliance on, Rule 144A under the Securities Act, in transactions exempt from, or not subject to, the registration requirements of the Securities Act.

     You should consider carefully the risks that we have described in “Risk Factors” beginning on page 4 of the prospectus dated October 7, 2003.

     Neither the Securities and Exchange Commission nor any state securities commission has approved or disproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representatives to the contrary is a criminal offense.

The date of this prospectus supplement is February 26, 2004

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FORWARD-LOOKING INFORMATION
This report may contain forward-looking statements, which are intended to be subject to the safe harbor protection provided by Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. These statements relate to future events or our future financial performance and involve known and unknown risks and uncertainties that may cause our actual results or performance to be materially different from those indicated by any forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “forecast,” “may,” “will,” “could,” “should,” “expect,” “plan,” “believe,” “potential” or other similar words indicating future events or contingencies. Some of the things that could cause our actual results to differ from our expectations are: economic conditions; the continued impact of terrorist attacks, global instability and potential U.S. military involvement; our significant indebtedness; downgrades of our credit ratings; the competitive environment and other trends in our industry; changes in laws and regulations; changes in our operating costs including fuel; changes in our business plans; interest rates and the availability of financing; liability and other claims asserted against us; labor disputes; our ability to attract and retain qualified personnel; and inflation. For a discussion of these and other risk factors, see Item 1 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2002. All of the forward-looking statements are qualified in their entirety by reference to the risk factors discussed therein. These risk factors may not be exhaustive. We operate in a continually changing business environment, and new risk factors emerge from time to time. Management cannot predict such new risk factors, nor can it assess the impact, if any, of such new risk factors on our business or events described in any forward-looking statements. We disclaim any obligation to publicly update or revise any forward-looking statements after the date of this report to conform them to actual results.

ITEM 12.
Results of Operations And Financial Condition
Subsequent to our January 28, 2004 press release summarizing our fourth quarter and full year 2003 financial results, further review of the Mileage Plan liability and related deferred revenue as of December 31, 2003 revealed that these amounts had not been fully adjusted to reflect planned deletions of certain accounts with expired miles. The consequent adjustment to reduce the total Mileage Plan liability and deferred revenue estimate from $344.4 million to $336.0 million resulted in an $8.4 million (pretax) increase in total revenues for the fourth quarter and full year. Our adjusted 2003 fourth quarter consolidated net loss is $16.1 million and our 2003 full year consolidated net income is $13.5 million.

The attached schedules provide our revised financial results for the fourth quarter and full year 2003. The supplemental data is attached as Exhibit 99.1.

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