CALGARY - A federal arbitrator has ruled that WestJet's unionized pilots will also fly its new ultra-discount carrier Swoop that's set to launch next week.

Capt. Rob McFadyen, chairman of WestJet's Air Line Pilots Association, says the decision means the airline can no longer outsource Swoop flying, a major disagreement in recent negotiations.

Swoop will recognize the union as the exclusive bargaining agent for all Swoop pilots, who will be on the airline's one seniority list and fly aircraft at Swoop terms and conditions.

WestJet and the union will now make a joint application to the Canada Industrial Relations Board to amend pilots association's bargaining certificate to include Swoop flying.

The parties also agreed that WestJet and Swoop are common employers.

The two sides scheduled mediation/arbitration dates over the summer to address all remaining issues.