By 2023, Dietrich plans to launch a car that takes off and lands vertically without needing a runway, so it can be used in urban environments.
The potential of so-called VTOLs and other drone concepts is being recognized by other automakers besides Audi and Geely.
Daimler acquired a stake in a German air-taxi startup called Volocopter, displaying a version prominently outside its trade fair hall at last September's Frankfurt auto show.
Aston Martin CEO Andy Palmer believes air travel will be a crucial part of future transportation. In July, the British company unveiled the Volante Vision Concept at the Farnborough air show in England.
It said the three-seat VTOL vehicle previews a potential flying autonomous hybrid-electric vehicle for urban and inter-city air travel.
Porsche is considering whether to develop a flying car, too. Sales chief Detlev von Platen, a hobby pilot himself who used to own a Piper Saratoga prop plane, headed to Italdesign's stand during this year's Geneva show to admire the Pop.Up Next and talk with the company's CEO, Joerg Astalosch.
"This is a field which we are looking at seriously," von Platen said. "So far the progress we have made and the analysis of potential concepts gives us a lot of confidence. We are not talking about a fantasy — it's feasible."
Porsche is looking at a range of ideas, he said, from a completely autonomous flying vehicle where you just push a button, to something that gives customers the possibility of piloting the aircraft without a license.
In the case of the latter, the onboard system would assume control should the occupant depart from a specific set of predetermined parameters referred to as the flight envelope.
However, Porsche would not try to build its own. "If we do this, we will go with partners," von Platen said.
Also taken by the idea is Philipp von Hagen, head of portfolio management for the Porsche and Piech family holding that controls the VW Group. "The flying car as a regular means of transport can become a reality by 2025," von Hagen said. "Drones are agile and quiet due to their electrical propulsion and both more affordable as well as more environmentally friendly than today's helicopter."
Research indicated that the market could reach $32 billion (about 27.4 billion euros) by 2035, he said.
Uber, Google interest
Unsurprisingly, tech companies are also attracted to the potential. Uber Elevate, a division of the ride-hailing giant, imagines a future where uberAIR flying taxis ferry passengers from one "vertiport" to the next. This could cut the 32 km commute between India's bustling economic center of Gurgaon and downtown New Delhi from a staggering 100 minutes to just six, for example — all for only $37 (about 32 euros), it estimates.
In early May, the company announced at its second annual Uber Elevate summit that it was partnering with none other than the U.S. National Aeronautics and Space Administration (NASA) to advance its goals.
"Urban air mobility could revolutionize the way people and cargo move in our cities and fundamentally change our lifestyle much like smartphones have," Jaiwon Shin, an associate administrator at NASA, said after creating the agency's first ever agreement specifically focused on researching the technology.
Uber isn't the only San Francisco native reaching for the sky. Sebastian Thrun, an artificial-intelligence expert and the father of the autonomous-car program that eventually became Waymo, is CEO of a startup backed by Google founder Larry Page that also aims to commercialize this idea.
Thrun's company – called Kitty Hawk after the site where the Wright brothers took their maiden flight in 1903 – unveiled Cora in March.
This experimental two-man aircraft uses one dozen vertical rotors to get airborne before a separate propeller in the rear takes over, helped by two wings spanning 11 meters to maintain lift. Cora, entirely powered by electricity and autonomously piloted, can reach speeds of 180 kph and has a range of about 100 km.
For the moment, startups such as Kitty Hawk and Terrafugia are still working on concepts, and it is unclear which approach will win acceptance in the market.
Some, like the Volocopter, rely only on rotors for lift and propulsion. Attaching wings to help maintain elevation can reduce a battery's power consumption, but it adds structure and weight, which pushes up the power requirement during liftoff and touchdown.
"The key will be coming up with the best architecture to generate lift during forward flight, some of which would then come from harvesting the [air] velocity flowing over some static surfaces rather than only from the rotors," said Airbus' Cousin.
He thinks that three main challenges must be addressed to bring the technology to market, only one of which is reducing the cost to a third or even a quarter of that needed to operate a twin-engine helicopter. Much like autonomous cars, other key factors are safety and social acceptance, including noise pollution.
Typically, the rotor tips on a helicopter move at close to supersonic speed, with the blades constantly flying through each other's wake. That creates the characteristic loud chopping sound ill-suited to the needs of urban transport. "Noise reduction is one of our major targets," Cousin said. "The vehicles have to be much quieter than helicopters, which are too noisy to operate in cities today."
The best way this could be achieved is by turning the rotor blades slower. While that sacrifices performance, it is much easier to do this with electric propulsion than gas turbines, Cousin said. Once the vehicle has created sufficient lift to take off, then noise becomes less of an issue because it can simply fly higher.
"The vehicles also have to be fundamentally safer," Cousin said. "Helicopters are designed to achieve a certain level of safety, which only works when the number of hours you're flying is relatively small, as it is today. If you start flying millions of hours per year, then the statistical accident rate would just be unacceptable in a city."