The Montreal-based airline said labor negotiations with its 10,000 flight attendants are at an impasse and warned that the carrier may begin to shut down operations as early as Saturday without an agreement.

Air Canada says it is beginning a "phased wind down" of most of its operations after thousands of flight attendants voted to strike.

Air Canada said it will start cancelling flights on Thursday ahead of a possible strike by its flight attendants, which the airline said will allow for an orderly shutdown of Canada's largest airline.