The Transition can reach around 115 km per hour on the road and 185 in the air. It flies using a 87-litre tank of automotive fuel and burns 19 litres per hour in the air

Mann questions the size of the market for the Transition. The general aviation market has been in decline for two decades, he said, largely because of fuel costs and the high cost of liability for manufacturers. Also, fewer people are learning how to fly.

"This is not going to be an inexpensive aircraft to produce or market," he said. "It has some uniqueness, and will get some sales, but the question is, could it ever be a profitable enterprise?"