Air Canada says technical systems 'beginning to come back online'

After several hours of delay late Tuesday night, Air Canada said its airport systems, check-in and call centres were "beginning to come back online" following a technical problem.

But many travellers could still be faced with delays and cancellations, the airline says.

"We intend to operate our full schedule today plus five extra flights and some upgauged flights (larger than normal aircraft) in order to move customers affected last night," Air Canada spokesperson Peter Fitzpatrick said in an email to CBC News on Wednesday.

"There were a small number of flights cancelled this morning due to aircraft being out of position this morning due to last night's cancellations, but overall we are anticipating a normal day."

Several passengers took to social media Tuesday to report being stranded in cities across Canada and the United States.

The airline tweeted just before 10:30 p.m. ET that it was working to resolve the issue. Several hours later, the airline tweeted that the systems were coming back online.

"We're still expecting some flight delays and cancellations, but we are working hard to move as many customers as possible this evening and we are putting on additionalcapacity to transport customers affected tonight on flights tomorrow," a statement from the airline said.

Robin Smith, a spokesperson for the Greater Toronto Airports Authority, said the system was down from approximately 9 p.m. Tuesday to 12:20 a.m. Wednesday.

Smith said the GTAA was temporarily removing restrictions around nighttime flying for Air Canada flights that were delayed by the technical problems.

Even after the statement from Air Canada reporting that systems were starting to come back, many passengers complained on Twitter of ongoing issues with the check-in system and the call centre.

CBC'sGian-PaoloMendoza talked to travellers stuck in Vancouver late Tuesday night.

Ariel Vernon said she was heading to the Interior of B.C., where she's building a house

"They're pouring the foundation at 8 o'clock tomorrow morning, so I'm going to miss it."

Traveller Cartel Cutler said he was forced to cancel and delay business meetings.

"My whole day is shot tomorrow," he said.

Air Canada urged travellers to check the status of their flight before heading to the airportand apologized for the inconvenience.

At the peak of the system-wide outage, the Toronto airport's website showed delays of more than two dozen Air Canada flights.