Air Canada says airport systems, check-in and call centres are beginning to come back online after an outage affected flights throughout the country.
Spokesman Peter Fitzpatrick says the airline still expects flight delays and cancellations, but it is trying to accommodate as many customers as possible.
He adds some affected customers will be put on flights Wednesday.
Toronto Pearson International Airport, as well as the airports in Calgary and Vancouver, say they are working to support Air Canada.
At the peak of the system-wide outage, the Toronto airport's website showed delays of more than two dozen Air Canada flights.
Fitzpatrick says customers should check their flight status on their local airport websites or sites such as flightaware.com.