The accident took place at a little-used former US air base in the town of Bitburg, in the western part of Germany, during an 11-car race organised by the local Porsche club.
"It was a miracle that no one was hurt. There was considerable damage done to the plane and the car," Klaus Schnarrbach, spokesman for the Bitburg police, told Reuters.
Concentrating hard on his racing, the shocked driver had not noticed the plane behind him until it landed on top of his car.
He slammed on the brakes, and this sent the plane crashing to the ground.
"The aircraft managed to stay steady on the roof at first," said Schnarrbach, adding the pilot faced possible charges of negligence.
"They probably couldn't have done it that well if they had tried," he said.
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