Why flying cars won't take off

Flying cars are starting to appear on our, ah, radar screens once again.

We featured them in an article last Friday, and CBS News' 60 Minutes did the same over the weekend.

The concept of flying cars has been around since the Jetsons, of course: ideally, we'll be able to take off vertically, cruise at 200+ miles per hour, and be safe no matter what the weather is like.

Now consider why flying cars aren't likely to become a reality anytime soon:

* Cost: The four-seater M400 Skycar is supposed to sell for $500,000, which is far more than a four-seat airplane, though it is comparable to high-performance helicopters. But the half-million dollar suggested price tag is just that -- suggested. The first Skycars may be closer to a million dollars, which happens to be the cost of a used Lear Jet that can cross oceans in comfort at nearly Mach 1.

* Regulations: The 60 Minutes article says you won't need a pilot's license to fly the personal helicopter called the AirScooter under 400 feet in non-restricted air space. Whoever wrote that is not a pilot. Let's assume you can AirScooter all you like over the fields of the midwest. But if you live near a metropolitan area, you may be in restricted airspace. Which means trying to interpret sectional and terminal charts like these. And avoiding no-fly-zones that the government randomly establishes (unless you like close encounters with F-15s).

* Automation: One way around this problem is to turn all the navigation over to computers. The 60 Minutes piece alludes to this, saying that NASA's Highway in the Sky program could control aircars remotely. Sure, that could work -- until a bird takes out the aircar's antenna, or there's a power outage on the ground, or there's a bug in the control software, and so on. Then you need someone who actually knows what they're doing at the flying car's controls. Which means training perhaps akin to what a recreational pilot learns, which means fewer people are likely to sign up for a flying car.

* Weather: How many people would buy a car they can only drive on clear, sunny days? It would be like buying a convertible without a top. Many people used to commercial jets don't realize that smaller aircraft are at the mercy of the elements far more than automobiles. Icing is perilous; wind gusts and turbulence are dangerous; flying into clouds or fog is prohibited by law unless you have an advanced license called an instrument rating. Thunderstorms must be avoided at all costs. (Makes a flying car somewhat less useful, doesn't it?)

* Safety: If the humble two-seater Cessna 152 suffers an engine failure at 10,000 feet, it can glide for 16 miles at 60 knots, flaps up, with no power, according to the plane's manual. That increases the odds of the pilot finding a landing site that he or she can walk away from. Most of the flying car designs I've seen can't glide in the event of an engine failure. There's a reason the Cessna 152 can glide so well: its wings are over 33 feet wide. Try fitting that in your garage.

That said, I don't mean to take away from the incredibly innovative work that aircar designers are doing. They're revolutionizing the industry in a way we haven't seen in decades. (I wonder how much of that stagnation was due to out-of-control product liability lawsuits that nearly bankrupted small aircraft manufacturers.) As technology improves, we may eventually see a flying car that solves the problems above. Just don't look for one anytime soon.