Air Canada suspended plans to restart operations Sunday after the union representing 10,000 flight attendants said it will defy a return to work order.

Canada’s government forced Air Canada and its striking flight attendants back to work and into arbitration Saturday after a work stoppage stranded more than 100,000 travelers around the world during the peak summer travel season.

The decision by the union representing the 10,000 workers means that travel chaos will continue for at least a second day. Air Canada said it had suspended its reopening plan until Monday evening.