United Airlines is cutting 240 jobs in Canada by outsourcing work in Vancouver, Calgary and Toronto. The cuts take effect in 90 days.
United's Toronto operations will lose 95 jobs, Vancouver will lose 84 positions, and Calgary will see 61 jobs cut.
"These were difficult decisions, but necessary as we must continually look for new opportunities to run a more efficient and financially sustainable business,” the airline said in an email statement to CBC News.
"Based on a competitive bid, United made the difficult decision to outsource the above- and below-the-wing functions at three Canadian stations: Vancouver, Calgary and Toronto."
The airline said it would be "talking to the vendor" about providing preference to laid-off United employees for jobs.
No flights are being cut.
The workers being cut in Calgary and Vancouver are members of the International Association of Machinists and Aerospace Workers.
The Toronto workers are customer service representatives and are members of Unifor, the union formed last year by the merger of the Canadian Autoworkers and the Communications, Energy and Paperworkers unions.
"This is a devastating blow to an experienced workforce that has a proven record of performing their duties to the highest standards," said Unifor national president Jerry Dias in a statement. He blamed "inadequate laws protecting the rights of workers in federally regulated sectors."
Air Canada and United Airlines are in a joint venture that includes co-operation and revenue sharing on transborder flights between the two carriers. Both airlines are part of the Star Alliance,
United Airlines became the world's biggest airline following its 2010 merger with Continental Airlines but lost that title last year to American Airlines when it merged with US Airways.