Air Canada began canceling flights Thursday ahead of a possible strike by its flight attendants that could impact hundreds of thousands of travelers. A complete shutdown of the country's largest airline threatens to impact about 130,000 people a day.

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 canceled most of its flights over the next few days to prepare for a strike by flight attendants. Some travelers may end up stranded as a result.