However, a Slovakian firm has said it has finally cracked the problem - and it will sell in it just two years.

The AeroMobil can fly 430 miles on a tank of petrol - and when its wings fold down, it'll fit into a normal parking space.

Aeromobil is a 'flying car' that perfectly makes use of existing infrastructure created for automobiles and planes, and opens doors to real door-to-door travel,' the firm says.

When in its car configuration, it can fit into a standard parking space, and it also takes normal fuel pumped at every service station.

The latest version is the third generation of the craft.

'It is now finalised and has been in regular flight-testing program in real flight conditions since October 2014,' the firm said. 

At South By Southwest, Juraj Vaculik, co-founder and CEO of AeroMobil, spoke at a panel about the future of flying cars, predicting a world ahead in which these vehicles easily merge with existing transportation.

He says it will be on sale in 2017, and that the firm was also developing a self driving (and flying) version.

Tatiana Veber, an AeroMobil spokesman said: 'We have been developing the concept of a flying car since 1990.

'Our first model looked quite bizarre and it would have problems in the regular use.

'That was a signal to improve the concept of the flying car in a way to become an integral part of the regular road traffic.

'We got a positive feedback from several experts in avionics, which appreciated design and the technical solution of the process of transformation.

'The car is constructed to be fuelled at regular gas stations using the fuel for Rotax 912 ULS engine.'

AeroMobil says its third prototype is ready to be shown to the world this October 29th at the Pioneers Festival in Austria.

However, design is still not perfect- the wings fold into the back seat behind the driver when in car mode.

The firm has also released a video of it in action, driving through city streets then taking to the air.

'Aeromobil 3 is stylish, comfortable for both the driver and passenger, and exceptionally combines the performance of a sports car with qualities of an 'ultralight',' it says.

(dailymail.co.uk)