AAON Foresees Second Quarter Record Sales and Lower Earnings.

TULSA, Okla. -- AAON, Inc. (Nasdaq:AAON) today announced that it expects to report record sales for the second quarter ended June 30, 2004, while net income will be substantially less than the first quarter of 2004. The higher sales are attributable to a record backlog and some contribution of revenues from AAON Canada, Inc., acquired on May 5, 2004, despite closings of the Company's Tulsa plant for four days during the period due to computer and electrical outages. The lower earnings resulted from the continued impact of higher steel and copper prices and startup costs associated with a new coil project, a loss incurred by AAON Canada, Inc., equipment failures at the Company's Longview, Texas plant, which prevented coil production needed by the Tulsa facility, and the above-referenced plant closings.

This press release contains "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933. Statements regarding future prospects and developments are based upon current expectations and involve certain risks and uncertainties that could cause actual results and developments to differ materially from the forward-looking statements.