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.

The Canadian carrier has canceled all flights ahead of a possible flight attendants strike, threatening to disrupt travel for more than 100,000 passengers per 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.