Some travellers are heading into the long weekend on edge, as WestJet begins its first round of cancellations ahead of a possible strike by flight attendants.

The clock is ticking down toward a strike deadline that could see 4,400 WestJet flight attendants hit the picket line as soon as Sunday.

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