A strike by 10,000 Air Canada flight attendants has been deemed illegal, and workers ordered back on the job. The ruling from the Canada Industrial Relations Board comes after the flight attendants defied an earlier return-to-work order that also told them to submit to arbitration.

Air Canada and the union representing 10,000 flight attendants resumed talks late Monday for the first time since the strike began over the weekend. The strike is affecting about 130,000 travelers a day at the peak of the summer travel season.