When asked the question: "What 'Back to the Future 2' products do we want?" the answer is pretty much always hoverboards. But as new machines, such as the amazing Flyboard Air, bring us nearer to what Marty McFly rode in the movie, we're still no closer to that other mystical symbol of the future: the flying car.

Or are we?

Google co-founder Larry Page has been secretly funding a pair of startups that are working to create "flying cars." The internet entrepreneur has sunk more than $100 million into Zee.Aero, which is located next to Google's Mountain View, California HQ, since its inception in 2010. The news comes from Bloomberg Businessweek, which cited ten people with knowledge of the matter.

The company has apparently hired staff from the likes of NASA, Boeing, and SpaceX, and developed a pair of prototype "plane-like" vehicles that locals claim to have seen hovering overhead. Both have a narrow body, a cockpit with room for one person upfront, and a wing at the back. One looks more like a conventional small plane, while the other has propellors dotted down the sides.

A patent filed in 2012 says one of the aircraft is capable of vertical takeoff/landing and is described as a "safe, quiet, easy to control, efficient and compact aircraft."

The second startup that Page is backing, Kitty Hawk, is working on a competing vehicle, one with a different type of design that's more like a giant quadcopter drone. The company, which is led by Google X founder Sebastian Thrun, contains staff from Zee.Aero and some from Aerovelo, the startup that won the $250,000 Sikorsky prize in 2013 for building a human-powered helicopter that could stay in the air for more than a minute.

Not all the designs are able to work as both cars and planes, but they're another step closer to the 'true' definition of the term "flying car." There could be one big problem, though: according to Bloomberg, Page said if his involvement with the companies was ever made public, he'd instantly withdraw from them.

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