The union representing mechanics at

UAL's

(UAL) - Get Report

United Airlines voted to authorize a strike after rejecting the latest contract proposal.

Thirteen thousand union members, represented by the International Association of Machinists and Aerospace Workers, could walk out as early as Feb. 20, although the two sides have pledged to keep talking.

UAL's latest proposal included pay raises of up to 37%. It was rejected by some 68% of those voting, while 86% voted to authorize the walkout.

Management remained hopeful for a resolution.

"If progress is made, and there is no reason to believe that it can't be, then we anticipate that another vote will occur by mid-March, without interruption of operations," Chief Executive Jack Creighton said in a statement.

UAL recently accepted recommendations from the Presidential Emergency Board that the airline offer mechanics raises, after previously saying it couldn't afford them. UAL lost $2.1 billion in 2001.