Air Canada suspended all operations on Saturday as more than 10,000 flight attendants went on strike after a deadline to reach a contract deal passed, leaving travelers stranded during the peak summer travel season.

Hugh Pouliot, spokesman for the Canadian Union of Public Employees (CUPE), confirmed the strike started after no agreement was reached, prompting the airline to halt operations and begin locking flight attendants out of airports.

The strike follows a bitter contract dispute between Canada’s largest airline and the union, which rejected the airline’s request for government-directed arbitration. Such arbitration would have removed the union’s right to strike and allowed a third-party mediator to decide the new contract terms.

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Federal Jobs Minister Patty Hajdu met with both parties Friday night, urging them to make greater efforts to reach an agreement. “It is unacceptable that so little progress has been made. Canadians are counting on both parties to put forward their best efforts,” Hajdu said in a statement.

Air Canada operates around 700 flights daily, and the shutdown could affect about 130,000 passengers each day, including some 25,000 Canadians stranded abroad. Travelers impacted by the strike are eligible for full refunds or alternative travel options, though flights on other carriers are largely full due to the summer travel peak.

Air Canada and the union have been negotiating for eight months but remain far apart on pay and unpaid work performed outside flight hours. The airline’s latest offer proposed a 38% increase in total compensation over four years, while the union said the 8% raise in the first year was insufficient to offset inflation.

Air Canada Chief Operating Officer Mark Nasr warned it could take up to a week to fully resume operations once a tentative deal is reached.