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

Air Canada has delayed restarting flights until Monday evening after the union representing 10,000 flight attendants vowed to defy a government-backed back-to-work order.

Air Canada cancelled hundreds of additional flights on Sunday after the union representing its flight attendants announced the workers would remain on strike in defiance of a back-to-work order. The Canadian Union of Public Employees said it filed a challenge in Federal Court on Sunday to an order by the Canada Industrial Relations Board that said its members must return to work by 2 p.