Henry Ford claimed in 1940 that flying cars were on the horizon. More than 75 years later and his vision is still way ahead of what technology and the regulators will allow. It is getting closer, however, just as the idea of what Uber calls “on-demand urban air transport” becomes ever more appealing as a means of escaping gruelling traffic jams and packed commuter trains.

There are as many as 40 companies currently developing flying cars, or what would more accurately — if less alluringly — be called roadable aircraft. In some cases these are effectively real-life versions of Chitty Chitty Bang Bang — four-wheeled machines that drive on the road with wings that sprout on demand. For commercial use, the most promising prototypes are essentially battery-powered helicopters that can lift off and land vertically, and use multiple rotor blades.

Google is backing a recreational version that looks like a cross between a hovercraft and a jet ski. Airbus plans to test its own version, Vahana, by the end of this year. And Uber is now piling in with ambitions to demonstrate flying vehicles by 2020 in Dubai and the Dallas-Fort Worth area.