After eight months at the bargaining table, the union representing WestJet pilots is calling a strike vote.

May 19 is the earliest that pilots could strike following a federal conciliation and cooling off period.

Pilots began voting today and have the next 15 days to decide whether to give their union authority to strike. The union says the two sides remain far apart at the bargaining table on many issues, particularly working conditions, compensation and job security.

"I don't believe we would ever take a strike vote lightly. This is something we take very seriously and we wouldn't be in this position unless we thought it was necessary to come to a contract," said Rob McFadyen, chairman of WestJet's Air Line Pilots Association (ALPA) master executive council, in an interview. "It doesn't seem like they are taking our issues seriously."

The union says it wants to continue negotiations and prefers not to strike. Further talks are scheduled between the two sides.

"The pilots are very united with the strike vote," said McFadyen. "I think there is a great deal of support for it."

Pilots voted in favour of forming a union in May 2017, and their counterparts at WestJet Encore followed suit in November.

Negotiators with the company and pilot group held two negotiating sessions where they haven't passed any tentative agreements on any section of the contract, according to the union.

"There's certainly more that unites us than divides us. When rational people continue to sit round a table, you generally find a rational outcome," said WestJet CEO Ed Sims during a CBC interview earlier this month. (Kyle Bakx/CBC)

"We recognize that a strike authorization vote is a common step by unions in context of the overall labour negotiation process," said WestJet CEO Ed Sims, in a statement. "We remain focused on successfully negotiating an agreement that will benefit our pilots and WestJet."

In an interview with CBC News earlier this month, Sims said he was confident that a deal would be reached in the next two months, before the airline launches its new discount carrier Swoop on June 20.

"We're at the stage where they are tabling their claims, we are tabling our response. It's interesting in negotiations, very often nothing is revealed until everything is revealed. We're at that critical juncture right now," he said. "There's certainly more that unites us than divides us. When rational people continue to sit round a table, you generally find a rational outcome."

Sims said he was comfortable working with unions at WestJet. It's a sharp contrast to former CEO Gregg Saretsky, who fought unionization and said he would "go down fighting" any union drives. Sims replaced Saretsky last month.

WestJet was forced to change its hiring strategy for Swoop, after a ruling by the Canada Industrial Relations Board last month in favour of the union. The airline was trying to recruit pilots from the main line to work for the new bargain carrier.