Flight attendants with WestJet, Canada's second-largest airline, went on strike Sunday in a dispute over pay. The Canadian Union of Public Employees, which represents the 4,400 cabin crew at the airline, announced the strike on its Facebook page. WestJet, which is a Delta Airlines partner, confirmed the strike and canceled more than 300 flights as of early Sunday, snarling travel plans in Canada in the middle of a three-day weekend. A key issue in the dispute was how flight attendants should be paid for duties performed while still on the ground. WestJet Encore flights operated on a Q400, as well as code-share flights operated by airline partners, remain unaffected.