MILWAUKEE, Jan 15 (Reuters) - A union representing pilots at Midwest Express Airlines on Tuesday said it has rejected a request for concessions management made shortly after the Sept. 11 attacks, citing no evidence of legitimate need. Midwest Express asked the pilots for concessions shortly after the attacks when it also froze the salaries of employees not under contract to cope with an erosion in air travel. The carrier cut its flight schedule 15 percent and laid off 450 workers, or about 12 percent of its staff, at that time. However, after reviewing public information, "we simply could not find evidence of legitimate need," Capt. Jay Schnedorf, chairman of the Midwest Express unit of the Air Line Pilots Association International, said in a statement. A comment from the airline was not immediately available. The union looked at U.S. Securities and Exchange Commission filings and comments from industry analysts, and company leaders could not provide evidence of legitimate need, Schnedorf said. "Clearly, these sources project our airline's recovery from the post-Sept. 11 downturn, and a secure financial and competitive position," Schnedorf said. Schnedorf, in a letter on Tuesday to Midwest Express' senior vice president of operations, said the executive council for the carrier's pilots union shared the same goal as management for a return to profitability, but does not believe concessions are necessary or warranted to achieve that goal. Shares of parent company Midwest Express Holdings Inc. (MEH) rose 90 cents, or 5.8 percent, in Tuesday New York Stock Exchange trading to $16.45.