Although Uber recently managed to bring a small pilot program of self-driving cars to the streets of Pittsburgh, the company still has a ways to go before its cars are going to drive themselves around without any human intervention. On top of that, national regulation for ensuring these sorts of cars operate safely and legally on US highways is still nascent. While Uber has a history of circumventing regulation where possible, it’s harder to do so when it comes to aircraft.

Holden said at the conference that Uber plans to bring these planes to consumers within 10 years, but that appears to be an aggressive timeline. The US has strict airworthiness guidelines for new aircraft (which can be avoided in testing as Facebook and Google have shown, but not in commercial use), and right now, US regulations don’t permit autonomous flight for delivery drones, let alone massive drones that carry people in them. Uber would need develop an entirely new type of aircraft and have it approved by a country’s aviation authority. That’s seems like a particularly daunting challenge for a company that has only had a robotics research facility for a little over a year.

Other companies are looking into similar concepts. At this year’s Consumer Electronics Show in Las Vegas, Chinese drone manufacturer Ehang showed off a large autonomous drone that can transport someone on its own about 50 miles. Organ transplant firm United Therapeutics has ordered 1,000 of them over the next 15 years, but much like Uber’s proposed craft, it’s not entirely clear how these would be received by the FAA, any other country’s aviation authority, or the general public.

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