After days of intense negotiations , WestJet flight attendants went on strike early Sunday morning, leaving thousands of travellers scrambling during the busiest stretch of the summer travel season.

More than 4,000 flight attendants represented by CUPE 8125 walked off the job at 12:01 a.m. MT on Sunday, capping nearly 11 months of bargaining with the Calgary-based carrier and a tense 72 hours that saw the airline cancel hundreds of flights pre-emptively.