Two small biplanes simulating a World War I dogfight collided Sunday at an air show in central Canada, killing both pilots instantly.

Witnesses said one plane came from beneath and collided with the second craft. Both burst into flames and crashed. No spectators were hurt, but the air show in Moose Jaw (search), about 120 miles north of the Montana border, was immediately canceled.

The pilots were members of the U.S.-based Masters of Disaster civilian aerobatics team. A third plane involved in the dogfight simulation landed safely.

Clive Tolley, executive director of the air show, said Canada's Transport Safety Board would be arriving Monday to launch an investigation into the crash.

"It was a civilian performance that has been practised many, many times and done in a safe manner many, many times," Tolley said.

Some relatives of the dead pilots had been at the air show and were taken to a nearby military base while officials tried to notify family members in the United States.

Additional information on the pilots was not immediately available.