Air Canada said Monday afternoon that it has resolved IT issues that disrupted departures and other operations.
Travellers were advised to check the status of their flights and check in at AirCanada.com before going to airports because the cancellation caused delays and some cancellations.
"We apologize for any inconvenience this situation has caused," Ben Smith, the carrier's president of passenger airlines said in a statement. "We appreciate our customers' patience and we have arranged additional staffing to get our customers on their way as soon as possible."
The airline has put a flexible rebooking policy in place so that customers can change flights without paying fees, depending on the availability of seats on affected flights.
Airports in Air Canada's key hub cities of Vancouver, Calgary and Toronto tweeted out earlier Monday that the airline's IT system was down, delaying flights and disrupting arrivals.
The disruption came two weeks after the airline had a computer issue that disrupted web and mobile check-ins and call centre operations and delayed boarding on some flights.
With The Canadian Press