About 500 flights would be grounded by midnight Friday, and it would take about a week to restore full operations once a labor agreement is reached, the company said.

Air Canada has started canceling flights ahead of a possible work stoppage by flight attendants that could impact hundreds of thousands of travelers.

Canada’s biggest airline is poised to start canceling several dozen flights Thursday ahead of a weekend lockout of flight attendants that threatens to throw travel plans for tens of thousands into chaos during the peak summer season.