Air travellers planning to fly WestJet may be concerned about potential disruptions from a strike, with dozens of flights already cancelled.

The Canadian Union of Public Employees Local 8125 gave the airline notice early Thursday morning, the union said in a post on its website.

WestJet, Canada's second-largest airline, is preparing to wind-down operations ahead of a potential strike or lockout by its flight attendants. But an agreement to gradually halt…