(CNN) -- Canadian authorities are investigating reports that debris fell Monday from a troubled airliner and calls saying that the debris fell in southern Ontario, damaging vehicles.
The incident centers around Air Canada 1 flight, which took off from Toronto at 2:10 p.m. ET, destined for Tokyo's Narita Airport, with 318 passengers and 16 crew members aboard.
One of the Boeing 777 aircraft's engines shut down after takeoff, prompting the flight crew to follow "standard procedure" and return to Toronto Pearson International Airport, said Air Canada spokesman Peter Fitzpatrick.
The crew requested an emergency landing, which Fitzpatrick said was standard because it gives certain planes first priority, though he also noted the aircraft involved is designed to run on a single engine if necessary.
The plane landed normally and passengers returned to the gate, according to Fitzpatrick. Constable George Tudos, spokesman for police in the regional municipality of Peel, said the aircraft returned to Toronto's airport at 3:53 p.m.
Yet more than an hour before that, around 2:30 p.m., people began reporting seeing smoke, and one spotted what might have been debris coming from a large airliner, according to the spokesman.
Peel Regional Police ended up receiving several calls from people reporting vehicles had been damaged by things that mysteriously plunged from the sky, said Tudos. As of about 4:30 p.m., three to five such vehicles were being investigated for damage.
No injuries have been reported on the plane or on the ground, added the spokesman.
Fitzpatrick, the Air Canada spokesman, noted around 5 p.m. that there had been "no confirmation at this time" that debris had fallen from his company's plane.
"There will be a full investigation into this incident, as there always is, and that will determine what happened," said Fitzpatrick.
Tudos, the Peel police spokesman, said officials from the national transportation agency Transport Canada are investigating.