The Calgary-based airline WestJet has signed a tentative agreement to avoid a labour strike threatened by the union representing its pilots. The strike would have forced the airline to ground the majority of its planes heading into a travel-heavy May long weekend.

An Air Canada flight departing for Toronto taxis to a runway as a WestJet flight bound for Palm Springs takes off, at Vancouver International Airport in Richmond, B.C., in a file photo. The Canadian Press/Darryl Dyck