Passengers who saw flights delayed or cancelled during this week's partial shutdown of Toronto's Pearson International Airport were expected to fly to their destinations by the end of Friday, according to an Air Canada spokesperson.

"Overall things have pretty much returned to normal operationally and the last of the delayed passengers are expected to move today," said Peter Fitzpatrick.

WestJet flyers who experienced cancellations at Pearson have all been booked on new flights, according to Robert Palmer, WestJet spokesperson.

Meanwhile, the CEO of the Greater Toronto Airport Authority is apologizing to travellers who were stranded at Pearson International Airport this week, after a ground stop caused hundreds of flight cancellations and delays.

"I would like to take this opportunity to offer an apology to all the passengers who were affected those two days based on the disruptions and frustrations they encountered, and the changes to their travel plans," CEO Howard Eng told CTV News Channel on Friday.

"Yes it is a little late, but I think an apology is still warranted."

Frigid temperatures of about – 40 C with the wind chill prompted the ground stop at Pearson on Tuesday, effectively halting all arriving North American flights. The shutdown resulted in more than 600 flight delays and cancellations, stranding passengers at the country's busiest airport.

Eng was not in Toronto during the event, but he said he was in constant communication with his staff, including an acting CEO who has the full authority to act on his behalf.

He said it was decided that it would be better for him to stay in communication, rather than trying to travel to Toronto and lose communication for four to five hours.

Eng added that the airport staff are "quite well prepared" for cold-weather events, but faced a number of extreme weather conditions including frigid temperatures, flash freezing, high winds and white outs.

"Everyone was working very hard, but because of the conditions, everyone was just taking a little longer to perform their duties," he said. "People were prepared, but not prepared to that extent."

Airport and airline staff will be meeting to have a major debrief to identify what went well and what went wrong, he said.

"We will learn from our mistakes."

With files from the Canadian Press