Air Canada withdrew its financial targets for the year as a strike by flight attendants entered its third day, forcing the country’s largest airline to cancel about 500,000 flights.

Many travelers remain stranded after 10,000 flight attendants for Air Canada went on strike early Saturday over failed negotiations regarding wages. On Sunday, Air Canada said it could not restart operations as planned after flight attendants ignored a government order to return to work.

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.