CALGARY - WestJet Airlines Ltd. and its 510 regional pilots have reached a tentative collective bargaining agreement.

The Calgary-based airline says the deal with WestJet Encore pilots will be presented to the Air Line Pilots Association (ALPA) for ratification. WestJet did not disclose details of the agreement.

It comes more than three months after an arbitrator set the terms for the first collective agreement between the company and its other 1,600 or so pilots, who are also represented by ALPA.

They voted in favour of joining the union in May 2017, marking a major shift in culture at the airline as it expands internationally.

Last August, the company's 3,000 flight attendants voted in favour of joining the Canadian Union of Public Employees to further unionize WestJet's workforce.

ALPA represents pilots at WestJet's main service as well as ultra-low-cost subsidiary Swoop and WestJet Encore.