Air Canada says travellers should be prepared for further flight disruptions as it works to return service to normal following a technical malfunction Thursday.
In its daily travel outlook, the carrier said that while its IT system is now stable, flights may be affected at nine of Canada's busiest airports, including Toronto's Pearson, Montreal, Vancouver and Calgary.
Thursday's outage led to more than 500 flights — over three quarters of its trips — to be delayed or cancelled on the day, creating what the airline says are "rollover effects" that may lead to further delays Friday.
"Air Canada has stabilized its communicator system and it is functioning normally. However, due to the effects of Thursday's IT issues on our schedule, some flights may be delayed this morning as we reposition aircraft and crew," it said in an emailed statement.
"Customers are advised to check the status of their flight before going to the airport. Our flexible travel policy remains in effect for customers to change their travel plans at no charge."
The source of the disruption was in the system used by the airline to communicate with aircraft and monitor their performance, which Air Canada has been in the process of upgrading.
On May 25, it grounded its planes for about an hour when the system experienced a separate issue, causing delays for nearly half of Air Canada's flights that day.
A total of 89 Air Canada flights, or 17 per cent of the airline's scheduled load, had been delayed Friday as of around 11:30 a.m. EDT, along with 32 cancellations, according to tracking service FlightAware.com.
An additional 40 flights with Air Canada Rouge saw delays, plus 19 cancellations.