The union representing mechanics at WestJet says its members voted overwhelmingly to reject a tentative agreement with the airline. The Aircraft Mechanics Fraternal Association, which represents some 670 aircraft maintenance engineers and other skilled trade positions at the carrier, says about 97 percent of its members cast a ballot against the deal.

WestJet says the result does not affect operations, but company president Diederik Pen called the result “deeply concerning.”

Pen says the deal would have made employees the best paid airplane mechanics in the country after “challenging” negotiations toward their first collective agreement.

The union has cited wages, outsourcing, scheduling and layoff protection as central issues in the bargaining process.

The two sides reached a tentative deal on May 6, two days after WestJet issued a 72-hour lockout notice to mechanics following their announcement of a strike vote.

Pen said, “We are committed to meeting with AMFA to determine next steps, although it is important to realize that the financial scope of the first tentative agreement must remain intact. Our goal remains to find a viable and reasonable path forward.”