The flying car concept took a while to become reality but in America a company is on the verge of offering a version to the public. While the cost may be high, so is confidence that there is a viable market.
Terrafugia Transition: flying cars roar into reality
You will have seen them before - but only in the movies.
Bruce Willis drove one when he was saving Milla Jovovich from the bad guys in The Fifth Element, and in Chitty Chitty Bang Bang Dick Van Dyke took all the kids for a picnic in another.
We are talking about flying cars and the concept is no longer confined to the big screen. In fact, they are already in the air.
The prototype of this latest take on an old concept took its maiden flight just over a year ago from Plattsburgh Airport in New York.
It lasted eight minutes and reached an altitude of 425 metres. Dubbed The Transition, it only made it into the air because it weighs just 440kg. A modern car, such as a Ford Focus or a Chevrolet Volt, weighs three or four times as much - without having a huge pair of wings strapped to its back.
That leap into the unknown was all down to new, lighter materials.
Since the flight, there have been developments. Terrafugia, the American company developing The Transition flying car, has plans for a vertical take-off and landing (VTOL) version, not unlike the US military's V22 Osprey but flying with a new box of tricks that Terrafugia believes will remove the really scary potential for what might happen when bad drivers take to the air.
The proposed Terrafugia TF-X would be a tilt-rotor flying machine that would take off and land like a helicopter, thus requiring a parking lot rather than a runway to fly. However, under the hood will be a gizmo that will not only fly the car for you, but keep potential "air hogs" out your way.
However, don't expect to be heading out for the weekend shopping in one any time soon. They are not designed to be town cars yet and the first commercial TF-X is a decade away and will likely cost north of US$500,000. Well north.
Even so ...
"This could open up personal aviation for all of humanity," says Carl Dietrich, Terrafugia's co-founder, chief executive and chief technology officer, who has spent seven years and just over $10 million in financing from angel investors plus $1.25m in defence money getting to this stage.
Where is that stage? Well, this start-up by a bunch of MIT graduates in the United States already has 100 orders for its first prototype, The Transition model. Designed for private pilots to be able to land on an airport runway, fold up the wings in less than a minute and drive right out on to public roads, it has a list price of $279,000. That will add up to more than $27m in sales - once the ordered vehicles start to ship some time between January 2015 and March 2016.
The Terrafugia TF-X is a different vision. It will have four seats, a small fuselage on four road wheels, stubby wings and a pair of electrically driven rotors that point vertically for lift-off, then rotate horizontally for level flight, powered by a gas turbine jet.
The TF-X electronics will manage all that, as well as the rest of the flight. The pilot just decides when to lift off. That's not new; some military aircraft couldn't fly without computers controlling stability.
What is new is that the US congress passed the FAA Reauthorisation and Reform Act last year, which gives the federal aviation administration (FAA) a green light to invest in new technologies, including next-generation air traffic control systems. One of the mandates is that by 2020 all aircraft will be required to broadcast their GPS position and velocity to all other craft. And that gave Mr Dietrich the idea.
"I thought, 'Wow, this infrastructure is really going to be there,'" says Mr Dietrich.
"This really does enable a semi-autonomous system to guide you where you need to go."
The self-flying part of the vision is largely a software issue, he says, albeit a big one to sell it to the FAA.
"It's an eight-to-10-year process," Mr Dietrich says, "but we believe it's possible to increase the level of safety while simultaneously making it easier to operate an aircraft."
If Terrafugia can meet those safety requirements, that could lead to a cascade of effects.
"As these vehicles get out there, it's likely there will wind up being more and more little take-off and landing zones," Mr Dietrich says.
If, and it's a big if, all goes well and this sort of personal aviation becomes commonplace city parks, fields and car parks might set aside space for it, he says.
But who is going to buy these devices?
The number of road kilometres racked up by Transition owners is likely to be small, says Terrafugia. With The Transition, the owner-cum-pilot-cum-more-money-than-sense might fly 400km from home to an airport near his summer house, then drive the final five or 10km.
Equally, The Transition also gives the pilot the ability to set down in bad weather and drive a couple miles to a motel. With the TF-X on the other hand, if you have a big-enough back yard, you could set the TF-X down at your holiday home.
"By directly addressing congestion and other transportation challenges currently being faced internationally, widespread adoption of vehicles like The Transition and TF-X could result in significant economic benefits and personal time savings," says Terrafugia's blurb.
"Preliminary conversations with the [FAA] about the TF-X concept have demonstrated their willingness to consider innovative technologies and regulatory solutions that are in the public interest and enhance the level of safety of personal aviation," the firm adds.
"Terrafugia is excited to be nearing production of The Transition and continuing to push the envelope of personal transportation."
But they are still clearing regulatory hurdles in both the automotive and aviation industries.
"It wasn't getting it into the air that was the hard part," Mr Dietrich says.
"It's the stuff after. But I do believe it will pay off in the end."