Air Canada's flight attendants defied a government back-to-work order as the Canada Industrial Relations Board (CIRB) on Monday declared their strike unlawful, reigniting disputes over eight months of failed contract negotiations and grounding the airline's recovery plans. The leadership of the Canadian Union of Public Employees (CUPE) has been ordered to direct its members to return to work, said Air Canada in a news release. According to the release, following a hearing on Sunday, the CIRB also directed individual members of the union to cease all unlawful activities and return to work. The CUPE responded that Air Canada's flight attendants will continue their strike, which means that the airline's plans to resume operations will be delayed once again. Mark Hancock, the National President of the CUPE, said that the union would not accept the government's decision. "We made it clear again that this work stoppage, this strike will end when we get a collective agreement that works," said Hancock. Inside the Toronto Pearson International Airport, staff set up temporary counters to assist passengers unaware of the strike. Most of the flight information screens showed Air Canada's flights as "canceled" or "delayed," with only a few marked as "on time." Air Canada said that, despite the ongoing strike by flight attendants, services may resume on Tuesday local time. "Our hope is that the outcome will be that our employer will come back to the table and negotiate. We will happily go back to work with a respectful contract," said Shanyn, a flight attendant. The airline estimated that 500,000 customers' flights have been canceled as a result. Despite eight months of negotiations on issues of compensation increase, ground pay, improved pensions and benefits, as well as increased crew rest, Air Canada has been unable to reach a tentative agreement with CUPE. SHOTLIST: Toronto, Canada - Aug 18, 2025 1. Various of strike at Toronto Pearson International Airport; 2. SOUNDBITE (English) Mark Hancock, National President of Canadian Union of Public Employees (CUPE): "Well, we made it clear again that this work stoppage, this strike will end when we get a collective agreement that works."; 3. Various of empty check-in counters of Air Canada; 4. Various of stranded travelers at airport; 5. Various of screen showing departure flights schedule; 6. SOUNDBITE (English) Shanyn, flight attendant (full name not given): "Our hope is that the outcome will be that our employer will come back to the table and negotiate. We will happily go back to work with a respectful contract."; 7. Various of screen showing departure flights schedule, staff member, traveler. [Restrictions: No access Chinese mainland]