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.

A labor relations board declared a strike by Air Canada’s 10,000 flight attendants illegal on Monday and ordered their union to tell them to return to work by midday.

Hajdu had ordered the 10,000 flight attendants back to work, saying now is not the time to take risks with the economy and noting the unprecedented tariffs the U.S. has imposed on Canada.