Almost as soon as cars were invented, man -- and woman -- began dreaming of cars that could fly.
For years, it has been the stuff of science fiction and fantasy, but experts say 25 years from now, that dream will become reality.
"We will have a flying car in the next 25 years. Make no doubt about it," Stanford University professor and world-renowned "futurist" Paul Saffo told "Good Morning America's Weekend Edition."
In fact, we're already closer than you may realize.
In a warehouse in Davis, Calif., an inventor named Paul Moller is building the M-400 Skycar, which he says will be able to take off and land vertically, hover, and fly at up to 300 mph.
Moller foresees a future where skycars routinely zip around taxis or personal vehicles.
"You will be able to get in your skycar, drive it electrically to a vertiport, two or three blocks from your home, program in your destination, and go directly to that destination with being involved in the process," Moller said.
The M-400 and several earlier prototypes have already flown, but only on a limited basis and not very high or very far.
But no one doubts the technology exists to produce a flying car. The challenge is to make it safe to operate, and that means turning the driver into a passenger.
"As you know on the ground most of the accidents are due to operator error so you have to pull that out of the equation in the air," he said. "You just have to computerize it."
Transportation experts say people will eventually turn to the skies not just out of a sense of adventure, but out of necessity: to escape gridlock on the ground.
"There's a lot more space in three dimensions than there is in two dimensions on a road," said Mark Jannot, editor in chief of Popular Science. "I think that's a clear advantage -- just sort of being able to kind of move over and around and up and down and get out of the way."
There are several other versions of flying cars in the works.
Researchers at the Massachusetts Institute of Technology are developing a combo car-and-plane. A Texas company is releasing something that looks sort of like a miniature helicopter.
Whatever it is that finally takes off, don't expect it to be powered by gas. More likely the fuel source will be electricity or hydrogen. And they won't be cheap, at least not initially. The first Moller skycars will probably run $500,000.
If you don't like the view from your flying car, you may prefer the one from an aircraft from Virgin Galactic, a high-flying offshoot of Virgin Atlantic Airways.
Unlike plane travel, on Virgin Galactic the transportation will be the destination; you go up to look down.
Virgin Atlantic has announced plans to launch the first of these aircraft two years from now.
The initial flights will cost $200,000, but that will come down as the flights become more routine. Virgin Atlantic is already taking reservations.
"I anticipate that that price will come down to within the $10,000-a-seat range for these suborbital flights within the next five [years] or 10 years, probably," Jannot said.
If going up and down doesn't suit you, by the year 2031 you may be able to check into a space hotel and stay aloft for a few days.
Robert Bigelow made millions in real estate, and he's spending a big chunk of it on trying to develop a module that's placed in orbit by a rocket then inflated to become a space hotel, a laboratory, or an astronaut training facility.
"This will be about 330 cubic meters, which is three times as large as anything flying now," Bigelow said about the module that his Las Vegas-based company is building and testing.
The expandable module could be converted into the first orbiting hotel.
"It's a huge gamble. It's somewhere between philanthropy and insanity," he said. "We are like the regional shopping center mall developer that is trying to build a structure that can accommodate a whole lot of different users."
Saffo definitely agrees that it's possible by 2031.
"It is bold. All the engineering makes sense," he said. "So, it is realistic. Unknown is how safe is it?"
A smaller version of the module was boosted into space last summer. Bigelow plans to put the full-scale module, dubbed Sun Dancer, into orbit in two years.
Full-size modules would actually have the volume of a 1,500-square-foot home. Inside are galleys, a kitchen area, a workout room, kitchen facilities, and three windows providing the best view outside of this world.
Even when the many safety issues are resolved, there is still the problem of how to get up to the space hotel and back.
But Bigelow isn't waiting. He believes that when -- and not if -- he builds it and puts it into orbit, they, the customers, will come.
"The best we can hope to do is try to make these destinations real and safe and functioning, and then it's, oh my God, we hope that other folks who are working in the transportation world are successful."