AeroMobil display their latest prototype of a flying car, in Monaco, Thursday, April 20, 2017. The light frame plane whose wings can fold back, like an insect is boosted by a rear propeller. The company says it is planning to accept first preorders for the vehicle as soon as later this year. (AP Photo/Claude Paris)

Flying cars might seem like the stuff of science fiction, but two prototypes were launched Thursday on the French Riviera, at an event showcasing "supercars" in Monaco.

Dutch and Slovak companies unveiled their designs as world premieres in the tiny well-heeled principality, where luxury automakers have gathered until Sunday for the Top Marques showcase event.

Bratislava-based Aeromobil, whose first prototype presented two years ago suffered an accident, is back with a "new generation" of flying vehicle named after the firm which makes it.

"We are taking reservations from today for deliveries expected in 2020, after the process of (regulatory) approvals is completed," the Slovak firm's spokesman Stefan Vadocz told AFP.

The Aeromobil vehicle, six metres long and with a fully-deployed span of nine metres, is a normal four-wheeled car which can unfold its wings to transform itself into a plane able to fly two passengers at a cruising speed of 260 km/h for up to 750 kilometres.

The price? Between 1.2 and 1.5 million euros, depending on options chosen.

Its Dutch rival for the futuristic vehicle type, the Pal-V Liberty, is the brainchild of Robert Dingemanse, whose company is based near Breda in the south of the Netherlands.

His crossover car-plane is more compact, at four metres long, and should be deliverable as early as next year, once official approvals are secured. He is already taking orders for a vehicle which will cost between 299,000 and 499,000 euros.

The Dutch flying car is in fact a gyrocopter with three wheels and a retractable rotor. It can carry two people at a cruising speed of 160 km/h for between 400-500 kilometres.

It is "one of the safest flying machines on the planet," able to fly "whatever the weather conditions," say its designers.

Users of the the Aeromobil and the Pal-V Liberty will require both a driving licence and a pilot's qualification.

© 2017 AFP