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

Air Canada flight attendants have said they will remain on strike despite a government-backed labour board’s order to return to work by 2pm ET (18:00 GMT), which they described as unconstitutional.

Air Canada flight attendants said on Sunday they will remain on strike and challenge a return-to-work order they called unconstitutional, defying a government decision to force them back to their duties by 2 p.