"We are in a situation where literally hundreds of thousands of Canadians and visitors to our country are being disrupted by this action," Prime Minister Mark Carney said.

Air Canada flight attendants said on Sunday (August 17) they will remain on strike and spurn a government return-to-work order they called unconstitutional that would send them back to their duties.

The union said no, setting up an almost unprecedented standoff with the Canadian government, which had requested the back-to-work order.