Do cars that can flutter through the sky and traverse the ocean depths sound like unimaginable inventions of a distant future? For Tesla Motors' CEO Elon Musk, they’re yesterday’s news.

"Maybe we'll make a flying car, just for fun," Musk told The Independent in a recent interview. “We could definitely make a flying car -- but that's not the hard part. The hard part is, how do you make a flying car that's super safe and quiet? Because if it's a howler, you're going to make people very unhappy."

Musk made the remarks after handing over the keys to the first five British owners of Tesla’s latest Model S car at an event in London over the weekend. The company’s second-ever vehicle can gun from zero to 60 mph in four seconds. Among its very first proprietors? Fifty Shades of Grey author E.L. James.

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Flying cars, however, are not the only vehicular mashup Musk currently has in mind. After he purchased the submarine car Lotus Esprit -- which was featured in the James Bond film The Spy Who Loved Me -- last year for more than $920,000, Musk says Tesla “will be making a submarine car” as well.

However, it would be less a marketable product than a joyful experiment, he said. “It can transition from being a submarine to a car that drives up on the beach,” Musk explained. “Maybe we'll make two or three, but it wouldn't be more than that. It's not like we'd sell it, because I think the market for submarine cars is quite small.”

Musk’s remarks about flying cars come as another automotive giant, Toyota, is also said to be experimenting with hovering vehicles -- although for markedly different purposes. Rather than bounding through the air, Toyota is studying cars that can hover slightly above ground to reduce friction, the company’s managing officer of technical administration, Hiroyoshi Yoshiki, said in a recent interview.

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