OTTAWA - The Canadian Union of Public Employees says it has been certified to represent 170 flight attendants at Swoop, the low-cost subsidiary of WestJet Airlines (WJA.TO).

The union was previously certified by the Canadian Industrial Relations Board to represent flight attendants at WestJet and its Encore regional carrier.

Almost 4,000 of the Calgary-based airline's flight attendants are now unionized.

CUPE is Canada's largest union with 680,000 members, including 15,000 flight attendants.