An official at Toronto's Pearson International Airport says staff will have a "debrief" to see what could have been done to mitigate yesterday's extensive delays that left passengers waiting for hours on planes and at luggage carousels.

Toby Lennox, the Greater Toronto Airports Authority's vice-president of marketing and stakeholder relations, spoke about the delays on CBC's Metro Morning on Wednesday, as travellers face more turmoil at the airport related to the extremely cold weather.

Lennox told host Matt Galloway that GTAA staff will examine what improvements can be made.

"I've listened to the comments of travellers and I really do feel for them."

Thousands of passengers arriving Tuesday morning waited hours — in some cases as many as five hours — for their planes to reach the gate, then hours more to claim their luggage. Some left the airport without their bags while unclaimed luggage covered the floor in some arrival areas.

The problem caused airport officials to issue a ground stop order early Tuesday to help deal with the backlog in processing arriving flights. The order prevents new flights from arriving. The ground stop was lifted just after 10 a.m.

The delays happened after overnight temperatures hit –25 C. Lennox said the cold weather caused equipment to ice up. It also meant more flights were diverted to Pearson, leaving the airport "overwhelmed" by incoming flights.

Passengers who spoke to CBC repeatedly complained about a lack of information updates. Another common complaint was a lack of staff on the ground to help answer questions about connecting flights and baggage.

Lennox said he expects communication will be a focus of the debrief.

"We could have done a better job with respect to the communications to passengers," he said. "It's an enormously complicated situation. There were far more arrivals then we could handle at the time due to the extreme weather.

"Everything started to slow down and ice up more than we expected."

More delays expected

Galloway asked Lennox if the airlines considered unloading passengers from the planes onto buses to get them into the terminal quickly. He said the airlines opted not to do this because it can be a slow and unpleasant process in cold, windy weather.

"The air carriers decided to leave the passengers where they are safe and warm," he said.

Wednesday won't be a normal travel day due to fallout from yesterday's extensive delays and cancellations caused by freezing temperatures.

As thousands of people are still trying to re-book flights, the airport authority issued a message on Twitter just after 5:30 a.m. Wednesday, warning passengers there could be a "slow startup" on Wednesday.

As of 6 a.m. ET, the GTAA website reported that about 400 flights operating out of Pearson had been cancelled. About 20 per cent of scheduled departures had also been cancelled.

Passengers turn to ground transportation

On Tuesday evening, some passengers unable to book new flights were arranging ground transportation to other airports, where they have a better chance of catching a flight.

airport.lines.pearson

Passengers at Toronto's Pearson International Airport spent hours in long lines Tuesday dealing with weather-related delays. The airport is warning there could be more problems on Wednesday. (David Donnelly/CBC)

"We are thinking of renting a car and driving back to Halifax," frustrated passenger Fernando Salazar told CBC News. "We can't get a flight until Friday."

Photos showed unclaimed passenger luggage clogging up floor space near carousels.

One man who spoke to CBC News found his bag among the thousands piled on the floor.

"I decided to take one last look. I got lucky," he said. "Someone could easily have nabbed it."

Passengers are encouraged to check their flight status before heading to the airport.