Cars That Fly
Modern mechanix promoted the concept of Hover-cars back in October 1958, the same year that Ford engineers demonstrated the Glide-air concept. Many science fiction movies feature futuristic hovercars; such as The Fifth Element, Blade Runner, A.I., I, Robot and many video games also.
According to Wikipedia, the closest real-world devices to hover cars are hovercraft.
Dream versus reality, how engineers approach development of Hover Cars differently
One thing car developers don’t seem to take on-board when trying to design hovercars, is weight versus power. Car developers appear to take a car and to make it fly, add more power. Unfortunately, they don’t seem to appreciate that powerful engines are heavy. For hovercraft to fly, they need to be lightweight, and use engines designed for high-power to low-weight applications, such as use in a microlight aircraft.
How a hovercraft engineer would design a hovercar
It you take a hovercraft and try engineer it to make it road legal, you would need to add wheels, lights and brakes. Hovercraft are very weight sensitive, and have more difficulty starting from an on-water start than when starting to hover on land, due to a pressure wave created on water known as The Hump. Typically, a hovercraft will lift 50% more weight when starting on land - payload is critical to success.
Depending on how many pies the driver and passengers have eaten, (your collective weight) the payload might lift half a ton of weight when starting on water. If you were to reverse engineer a hovercraft to design a hovercar, your passenger payload would diminish as you add the weight of wheels and lights. Hovercraft don’t tend to have brakes since they usually slide on the surface to stop.
To design a working hovercar, I suggest you start with a hovercraft and then make it roadworthy. Weight is very important, so use carbon fibre to ensure that the vehicle is light yet strong enough to withstand a few collisions - glass fibre would be too heavy and prone to disintegration on impact.
Keith Moon - The Who
Any hovercar designed to drive on roads will be subject to road-use legislation - Keith Moon, drummer with The Who once drove a hovercraft to his local pub following a ban for drink driving. The police stopped him, told him off for driving on the road, but he was reported to have explained to the police that whilst hovering, he wasn’t actually driving on the road, but a few inches above it! Legend!