A potential strike by WestJet plane mechanics would disrupt the travel plans of 250,000 customers over the Canada Day long weekend, the airline says, and cost it millions of dollars.

The Calgary-based carrier has already begun taking action, canceling about 25 flights Thursday and Friday in anticipation of possible pressure tactics from the Aircraft Mechanics Fraternal Association (AMFA), which could exercise a work stoppage as soon as Friday at 5 p.m. 1:30 a.m. (Mountain Time).

Already affecting some 3,300 customers, WestJet’s decision to begin restricting the movement of its 180 planes aims to avoid leaving planes in remote locations and catching passengers and crew off guard.

The mechanics union, which represents about 680 workers — the majority of them aircraft maintenance engineers who inspect every plane in service every day — has accused WestJet of “brinkmanship” and “false accusations.” It said Wednesday that the airline had asked the government to rescind its strike notice without informing its negotiators.

“In its own statement today, WestJet alleges that a strike by aircraft maintenance engineers would put “the company and the traveling public at risk at a critical time.” It is difficult to imagine a more inflammatory or offensive comment,” the union negotiating committee argued in a statement Wednesday.

WestJet has deemed the impact of a potential strike “catastrophic.”

WestJet Airlines President Diederik Pen called the decision to trigger flight cancellations “painful,” highlighting the consequences for customers.

Airplane mechanics first gave the carrier 72 hours’ notice of a strike on June 17, prompting WestJet to cancel nearly 50 flights last week before the two sides agreed to resume negotiations. The second strike notice arrived on Tuesday.

Union members voted overwhelmingly to reject a tentative agreement earlier this month and opposed WestJet’s application to the country’s labor court.

The Canada Industrial Relations Board said it needs more time and presentations from each side before deciding whether to establish a collective agreement through binding arbitration, as WestJet has proposed. last week.