Lineups were long, but moving, at Montreal's Trudeau airport Monday amid increased security measures.

Passengers wait to check in for U.S.-bound flights at Trudeau airport in Montreal on Monday. Tighter security, including a ban on most kinds of carry-on baggage, have been implemented in the wake of Friday's foiled attack on a plane heading to Detroit. (Graham Hughes/Canadian Press)

New restrictions and heightened security procedures were put in place over the weekend after a Nigerian man was charged with trying to destroy a plane during a transatlantic flight on Friday.

Umar Farouk Abdulmutallab had travelled from Nigeria to Amsterdam, and then on to Detroit, allegedly with an explosive device attached to his body.

Transport Canada outlined further regulations Monday evening designed to curtail the delays at airports countrywide.

"There were quite a few people at the check-ins in the early morning hours at Trudeau," the CBC's Valerie Boyer reported.

"A lot of passengers that I spoke with were surprised with how many people were in line. Many people had arrived at least three hours early for their flights."

By midday, the situation appeared to be well under control, the CBC's Amanda Margison reported from the airport.

"Right now inside the airport it's pretty relaxed. There is not too long a wait," Margison said, adding: "Things are really moving right along."

Still, officials continued to advise people to allow more time to get through the airport.

"Aéroports de Montreal recommends passengers travelling to the U.S. to arrive early at the airport and to allow extra time to clear security screening," the airport authority said in a statement on its website.

"An air transport security official told me there was a backlog where they were doing extra precautions such as patting down people," Boyer said.

Passengers and their carry-on baggage are subject to full searches both at screening points and again prior to boarding at the aircraft gate area, in compliance with new rules put in place by Transport Canada and the U.S. Transportation Security Administration.

As of Monday night, all carry-on luggage is prohibited on U.S.-bound flights, with key exceptions for medical, child-care, diplomatic and other special-needs baggage, Transport Canada announced.

Over the weekend, some flights out of Toronto's busy Pearson International Airport were delayed for as long as five hours, and some short-haul Air Canada and Jazz flights to the United States were cancelled because of the long lineups.