"We could definitely make a flying car -- but that's not the hard part," Musk told the Independent. "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."
"It can transition from being a submarine to a car that drives up on the beach. 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," he said.
Terrafugia Inc., a Massachusetts company founded by MIT graduates, has been already working on a flying car called the Transition. It's scheduled for a 2016 debut.