"We're not going to have a flying car, as people think of it, for a while," said Anna Dietrich, chief operating officer of Terrafugia, in a previous interview. "I would never say it's not going to happen, but today the infrastructure is not there, nor is the training, nor are the avionics that would make the training unnecessary. What makes sense right now is a roadable aircraft."

Dietrich said the idea of a such a vehicle is what fired up their imaginations and pushed them to found the company. The problem, however, is that the U.S. doesn't have the infrastructure in place to make roadable planes a viable alternative yet. There are roads, not runways, in front of houses, grocery stores and office buildings. And a sky filled with people who don't have pilot's licenses could be problematic at the least.

"You have to be a pilot to fly The Transition," said Dietrich. "And we just really don't have the technology to have an autopilot built in so people can just get in it and say, 'Fly me to the grocery store.' It's an airplane designed to be flown by a pilot in the infrastructure we already have, which is the airports."

She added that there are about 6,000 public airports in the U.S., and most people are, on average, within 20 miles of one. The idea, she said, is to take advantage of this underutilized infrastructure. A pilot can fly into a small airport, and instead of getting a rental car or waiting for a taxi to drive out to a rather remote spot, he can fold up the wings on the aircraft and simply drive off.

, though, may not make some passengers feel safe in the sky. Dietrich said making sure the wings stay erect while in flight was one of their biggest engineering challenges.