Dozens of international and domestic flights were diverted to Maritime Canada airports in the wake of Tuesday’s destruction of the World Trade Center in New York City and damage to the Pentagon.

Air travel around the country and in Canada came to a virtual standstill as all U.S. and most Canadian airports were closed and planes were grounded.

“All air movement from Canadian airports were grounded except for flights required for urgent humanitarian purposes and diversions by the FAA of international aircraft previously destined for the United States,” said David Collenette, Canada Transport minister, in a statement released late Tuesday morning.

Among those airports receiving diverted flights were the Halifax International Airport in Nova Scotia and the Greater Moncton Airport in New Brunswick.

By late afternoon, 20 planes had made unscheduled landings in Moncton, leaving 2,000 passengers wondering when and how they could get home.

William and Penny Behrens of Montville were prepared to drive to Boston’s Logan International Airport on Tuesday afternoon to pick up their daughter Electra, 22, whose USAir flight from Brussels, Belgium, was scheduled to land at 6 p.m.

When they contacted the airline, the Behrenses were initially told the plane was being diverted to Halifax. After checking again, they learned it had been diverted to Moncton.

Electra Behrens called her parents on her cell phone when the plane landed in Moncton early Tuesday afternoon. She told them that at some point when the plane was over the Atlantic Ocean, the passengers were informed the aircraft had encountered head winds and needed to land in Canada to pick up fuel in Moncton.

It was only when they were on the ground the passengers were told of the attacks on the World Trade Center. They were allowed to use the bathrooms and cell phones but were being kept aboard their aircraft, William Behrens said.

“Right now they are sitting on the tarmac,” Behrens said. “They [Canada] are being very careful about every plane and it’s going to be a real slow process to get them off.”

Passengers on planes diverted to Moncton were, for a brief time, not allowed to exit, said Andrew Phillips, a reporter with the New Brunswick Telegraph Journal’s Moncton bureau, Tuesday.

“That order was lifted after about a half-hour,” he said.

In addition, Phillips said planes landing in Moncton registered in or bound for the United States were kept separate from other international flights and under heightened security.

“The highest security was for the U.S. passengers,” he said. “Those planes were taken to a completely different area of the tarmac.”

With 20 planes on the ground, the Moncton airport was near capacity and handling the overflows from airports in Halifax; St. John’s, Newfoundland; and Gander, Newfoundland.

“On a normal day we see about 12 flights come through,” Mike Randall, Moncton airport spokesman, said. “Right now there are 70 [planes] in the air between St. John’s, Gander and Halifax.”

As passengers left their planes they passed through customs and were placed on buses for transport to a temporary facility established by the Red Cross in a sports coliseum.

“We are trying to make them as comfortable as possible,” Randall said.

Moncton area hotels already were full thanks to two large conventions going on in the city, Phillips said. “Residents have offered to billet people in their homes,” he said. “There are hundreds of planes up there and it’s been hard getting information,” William Behrens said. “USAir doesn’t even have a desk in Moncton.”

Planes diverted to the Maritimes are from British Airways, TWA, Continental, Transworld, Air France and USAir and were bound for points in the United States and Canada, Phillips said.

“I talked to one guy on an Air France flight who told me they were halfway between Paris and Canada when they were diverted to Moncton,” Phillips said. “He was wondering why they just couldn’t turn around and go home.”

Security was tight around the Moncton and Halifax airports where officers from the Royal Canadian Mounted Police patrolled the areas and the military was on a standby alert, Randall said.

“Transport Canada is on the highest alert,” Collenette said. “We will continue to monitor the situation and take whatever action is necessary.”

NEWS reporter Walter Griffin contributed to this report.