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 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.

Air Canada said it had reached an impasse with the union as the two sides remained far apart in contract talks