Canada's labour relations board has declared the strike by Air Canada's 10,000 flight attendants illegal.
The Canadian Industrial Relations Board (CIRB) ruled this morning that the Canadian Union of Public Employees broke the law when it defied a back-to-work order on Sunday.
The board called the union's actions "unlawful."
The decision orders union leaders to send their members back to work by noon today.
It also directs the flight attendants themselves to return to their duties right away.
"The members of the union's bargaining unit are directed to resume the performance of their duties immediately and to refrain from engaging in unlawful strike activities," said the directive.
Jennifer Webster, Vice-Chairperson of the CIRB, signed the order.
Air Canada asked the board to issue this ruling.
The airline suspended its financial guidance for the third quarter and full year today because of the strike and flight cancellations.
Flight attendants walked off the job early Saturday morning.
This halted about 700 flights a day and grounded Canada's largest airline.
Labour Minister Patty Hajdu used Section 107 of the Canada Labour Code on August 16 to order an end to the stoppage.
Hajdu directed the CIRB to help solve the dispute through arbitration.
The union ignored the order.
Air Canada then cancelled plans to resume some flights on Sunday.
Air Canada says it will restart operations this evening.
However, it remains unclear how this will happen given the ongoing dispute.
The airline and union negotiators cannot agree on wages.
Air Canada has offered a pay increase of 17.2% over four years.
The union says this offer does not account for inflation over the past decade.
Union members want fair compensation for work they do before planes take off.
