Authorities at Toronto’s Pearson International Airport, Canada’s busiest, warned travelers that a strike by about 700 ground crew workers could affect some flights Friday.

Airport officials advised travelers to check the status of their flights and said they would provide updates as they become available.

The striking workers are employed by Swissport and include baggage and cargo handlers, cabin cleaners and other ground crew.

Swissport works with several major airlines operating out of Pearson, including Air Transat, Sunwing, British Airways, Cathay Pacific, Air France, KLM and Lufthansa.

Picket lines were set up outside Pearson’s Terminal 3 and at a cargo terminal near Swissport’s main offices.

The Greater Toronto Airports Authority said it has a contingency plan in place to deal with the labor dispute.

The unionized Swissport workers went on strike Thursday night after 95 percent of them voted to reject a contract offer.

Teamsters Local 419, the union representing the workers, has said striking employees would not interfere with passengers trying to catch planes.

The union said Swissport is attempting to impose a three-year wage freeze on most workers and require a minimum 30-hour week to qualify for full benefits, and is also seeking the right to change schedules with 96 hours advance notice.

Swissport said it has bargained in good faith throughout contract talks.

(AP)