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 remains available to continue negotiations with its flight attendants as it winds down operations ahead of a potential labor disruption.

Negotiations between CUPE and Air Canada have ended in impasse. Air Canada still refuses to compensate flight attendants for all hours worked. The union has been firm: all safety-related duties should be paid at full hourly rate.