The union representing 15,000

United Airlines

mechanics has suspended its talks with the company.

The

International Association of Machinists and Aerospace Workers

said it believes United's negotiators don't have the authority to approve wage terms, which remain at a stalemate.

Shares of

UAL

,

(UAL) - Get Report

the parent company of United, closed down $1.31, or 3.3%, to $38 in

New York Stock Exchange

composite trading.