Air Canada has suspended plans to restart operations after the union representing 10,000 flight attendants decided to defy a return-to-work order.

The union for 10,000 striking Air Canada flight attendants said Monday they won’t return to work even though the strike, now in its third day, has been declared illegal.

The Canadian Union of Public Employees, which represents the flight attendants, had continued to strike even after the Canada Industrial Relations Board declared it unlawful.