The delays are a result of extreme cold triggering a ground stop at the airport on Tuesday, which prevented North American flights from landing for more than eight hours.
Corrinne Madden, spokeswoman for the Greater Toronto Airports Authority, said several factors, including a backlog of travellers and weather conditions at various destinations, could be playing a role in the new cancellations.
"It's a combination of things," she said.
"It's an airline's decision to determine whether or not a flight needs to be cancelled, so they may have consolidated some flights depending on the number of passengers," she said.
On Wednesday night, airlines were still advising customers to check online or by phone to confirm that their flight is operating before going to the airport.
The airport instituted the ground stop early Tuesday as the wind chill readings hovered around the -40 C mark and more than 600 flights were cancelled during the day.
Thousands of passengers have been sleeping at the airport and there are mountains of luggage waiting for pickup.
The GTAA said the ground stop was implemented because of how the cold was affecting equipment and to minimize time outdoors for employees.
The deep freeze enveloping the Toronto region abated somewhat Wednesday but the weather was still impacting flights at the airport.
Air Canada has advised travellers that severe winter conditions in eastern Canada and the U.S. northeast were still impacting its operations.
Air Canada vice-president Klaus Goersch said in a statement that the airline was "doing its utmost to get its customers to their destinations safely and as quickly as possible."
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