Air Canada said it would reach out via email or text to let customers know if their flights are canceled. The cancellations on Thursday included some long-haul overseas flights. By the end of Friday, the airline expects to cancel 500 flights.

Mark Nasr, Air Canada's chief operations officer, said that cancellations would go from "several dozens" on Thursday, to some 500 by the end of Friday, to the airline being "completely grounded" at the start of the strike on Saturday, in the absence of a resolution.

A possible strike by flight attendants has resulted in a scheduled lockout that may affect 130,000 passengers each day.