If you summon an Uber in 10 years' time, you will probably get a car that drives itself. But then again, you may not be travelling in a car at all. The taxi-hailing app is working on technology that would allow passenger drones to fly its users short distances around cities. He raises the prospect of a future in which skylines are dotted with Uber aircraft shuttling commuters back and forth.Jeff Holden, Uber's head of product, told technology website Recode that the company was researching "vertical take off and landing" (VTOL) technology. Instead of the helicopter-style rotor blade drones, VTOL aircraft have fixed wings like planes, enabling them to fly silently, while taking off and landing vertically.Amazon's delivery drones, currently being tested in the UK, use a similar technology to cut down on noise and extend their range.Holden said Uber wanted to "offer our customers as many options as possible to move around" and that the technology could be available within a decade."It could change cities and how we work and live," Holden said, pointing out that moving traffic from the road to the air could dramatically cut down on congestion and the time it takes to cross cities.He envisages aircraft taking off from and landing on the roofs of buildings.Uber is not the only one researching passenger drones. Earlier this year, Ehang, a Chinese company, unveiled the 184, an autonomous quadcopter drone designed to carry a single passenger. The 184, which could be released later this year, is expected to cost about $300,000.However, filling our skies with passenger drones within 10 years is an ambitious undertaking, and would require hundreds of pages of new regulations, not to mention consumers who would be willing to risk their lives in a small self-flying aircraft. ..