A brief wildcat strike on Wednesday stranded thousands of passengers at Canada's busiest airport, Toronto Pearson, where dozens of North American flights were canceled before ground crews returned to work around 8:15 p.m. EST (0115 GMT).

Air Canada canceled the flights to and from Pearson Airport after workers walked off the job earlier in the day.

"It relates to disciplinary action taken by the company against a number of employees," Air Canada spokeswoman Isabelle Arthur said. "We apologize to our customers for this inconvenience."

Officials at the airport told passengers waiting for information that all the flights -- some of which had previously just been delayed -- were canceled.

Frustrated passengers had started to make emergency plans, looking to other airlines to get them to their destinations or searching for space in area hotels.

Air Canada had also begun rebooking passengers on flights scheduled for Thursday morning.

Arthur said several international flights, which were delayed but not canceled, might still depart.

CBC News reported on its web site the dispute started on Wednesday afternoon after the airline, Canada's biggest, disciplined employees over clocking out at the end of their shifts.

Air Canada said the wildcat strike was being carried out by members of the International Association of Machinists and Aerospace Workers (IAMAW).

Connie Turner, spokeswoman for the Greater Toronto Airports Authority which operates Pearson, said the dispute involves ground service employees, including baggage handlers and workers who guide planes on the tarmac.

"We'll continue our airport operations with our other airlines and Air Canada will have to deal with what they have to deal with," she said.