So your hero needs a Cool Car. But what do you do when missiles, Nitro Boost and ejector seats don't suffice to show just how much of a badass he is? Simple: make it a flying car.
It's a quick way for writers to show just how super a superhero is, particularly if they are a Badass Normal. Or sometimes it's just a lazy way to demonstrate a show is set in the future. Nothing screams "futuristic city-scape" better than giant buildings with all the space between them crammed with flying shiny specks! Either way, you need a flying car! Just ask Dante and Randall.
The lack of flying cars in Real Life is a common complaint. The fact that they would for all intents and purposes be personal aircraft, and require the same regulations and specialized skill as planes and helicopters is a big reason why we haven't seen any in our lifetimes. Several flying cars have been invented in Real Life, but the concept has always ended up getting scrapped because said flying cars used up a lot of fuel... and had a penchant for crash-landing when they ran out. Most fictional cars handwave this by saying something about an Anti Gravity element in place. Even so, the air traffic that would ensue would be ungovernable (See Back to the Future Part II's hilarious deconstruction of this trope.)
If you still want your flying car, look into gyrocopters.
The Star Rocket Racer, the rarely-seen personal flying auto of both the Golden Age Star-Spangled Kid and Stargirl of the Justice Society of America. Ever since she got her Cosmic Rod she hasn't really had a need for it.
She-Hulk once had a flying car (a gift from a benevolent alien) but later lost it.
The comics' excuse was that the Supermobile was invented by Superman at a time he'd lost his powers, and needed something to help him fight Amazo. The car was capable of duplicating most of his powers, was constructed of a super-hard metal, and could shield him from kryptonite.
In Grant Morrison's Batman and Robin, Dick Grayson and Damien Wayne have a flying Batmobile.
A main staple in a lot of Antarctic Press comics. Asrial from Ninja High School converts a junked car into one as part of a challenge if she qualified for a job as a mechanic. It later used as the protagonist main transportation around town. Gina from Gold Digger patented (and often destroyed) "Gina Mobile" can turn into one when needed. And the heroes main transportation in the first half of I Hunt Monsters have one named Kirby that they use to get around the world.
Dude, it's the states. People there need the pleasure of driving like pedestrians need oxygen.
Subverted in the 2009 film with a young Kirk having a car which very decidedly could not fly, although he was still pursued by a cop on flying bike.
In Spaceballs, Lone Starr's flying Winnebago, the Eagle V. Princess Vespa's space car also qualifies. It was a Mercedes!
Perhaps the earliest example in film would be the small personal airplanes seen flitting amongst the buildings in Fritz Lang's Metropolis. They may not have looked like cars, but they seemed to fill the same function. This was probably also the Trope Maker for the whole "throw in some flying cars zipping between giant buildings to establish that we're in The Future" thing, and it remains popular to this day.
Cars featured a fantasy sequence by Lightning McQueen where he becomes Dinoco Lightning Storm McQueen, flies through the air, and dispatches evil tripods with missiles. Given that his very next fantasy involves opening nights and the Hollywood Walk of fame, he may have been fantasising about film-star ambitions.
In Cars 2, espionage agent Holly Shiftwell can fly. Mater manages to do so when he deploys both his parachute and his rocket thrusters.
The French film Fantômas se déchaîne ("Fantômas Unleashed") ends with the titular villain escaping in a Citroën DS that converts into an airplane.
The Number Of The Beast by Robert A Heinlein features one of the coolest cars of all time: Gay Deceiver. It doesn't just fly, it flies at hypersonic speed with retractable swing wings. It is capable of vertical take-offs and landings. It can even do semiballistic sub-orbital flights just past the edge of space. Oh, and it gets upgraded with a time machine that can visit alternate universes, some of them fictional ones, including Oz and Wonderland, as well as the ability to teleport within the same universe. Seats four, six if they're really friendly. Plus, it has a magic annex (thanks to one of those visits to Oz) with a pair of fully-functional bathrooms and a never-empty picnic basket. And a superintelligent talking computer autopilot with a wicked sense of humor and a sexy contralto voice. And a highly illegal (but well-hidden) laser cannon.
Pretty much all of Heinlein's "Future History" stories have flying cars. One of them (The Puppet Masters) even describes the North American radar net as being called the "No Sparrow Shall Fall" network that tracks every car (note there are about 250 million registered passenger vehicles currently in the USA). Despite the fact that he was considered one of the "kings" of Hard Science Fiction, he never would admit that flying cars are Awesome, but Impractical.
Aircars (4-8 passenger. Police/security models have varying armament options)
Lift Vans (mass cargo/passenger transport)
Anything larger will usually have orbital capability, moving into cargo shuttle or Drop Ship territory.
Dune's ornithopters (or just "thopter"s) probably count, although they may be more equivalent to helicopters. Note that ornithopters are a real invention, people have been attempting (and failing) to build practical ones for a century now.
Played hilariously straight in Good Omens when Aziraphale decides that 4-5 miles an hour on a small scooter is not fast enough to prevent the apocalypse. So he makes it fly. Very, very fast.
The volantors of Chasm City seen in Alastair Reynolds' Revelation Space series. Their most explicit appearance is in the novella Diamond Dogs.
Lowly Worm from the Richard Scarry books apparantly drives an apple-shaped car that also serves as a helicopter since its "leaves" actually function as the helicopter's blades. Except how the heck is he able to drive it if he doesn't have any arms?
In David Weber's Honor Harrington series, aircars have pretty much replaced ground cars, with the latter only being used on backward planets in fringe sectors. There are limousines, vans and sports cars, all of which can operate on different altitudes. They're also handy for disposing of troublesome people by certain less scrupulous organizations.
Stephanie Harrington shows how perfectly normal aircars are in the distant future, with Stephanie's parents, as a gift on her fifteenth birthday, allow her to take the test ot get her Aircar license.
Professor McClaine's flying car in Joe 90 has about the most uncool design a flying vehicle ever had.
Supercar from the Gerry Anderson series of the same name.
One of the first things Billy did in Mighty Morphin' Power Rangers once he started getting savvy with alien technology was make a flying Volkswagen Beetle he dubbed the "Rad Bug". Yes, they could, technically, teleport if they wanted to, but even Billy could tell that a flying car was cooler. And it did come in handy the times they couldn't teleport.
Also, Speedor of Engine Sentai Go-Onger / the Eagle Racer of Power Rangers RPM is a zord that's half-sports car, half-bird (condor in Go-Onger, eagle in RPM); and has a flight mode in line with the "bird" half. Kaizoku Sentai Gokaiger later introduces Speedor's son Machalcon (half-formula racer, half-falcon) who likewise has flight ability.
The third Doctor in Doctor Who (while grounded on Earth by the Time Lords) briefly used a futuristic flying car dubbed by fans as "The Whomobile".
More recently, the new series has "New Earth", which features flying cars. In its second appearance, the cars have the worst traffic jam in the history of the universe in "Gridlock".
The final scene of the Series Finale of 30 Rock has flying cars pass outside the window to show the story has advanced decades in the future when the never aging NBC President Kenneth is pitched a show totally set at 30 Rockefeller Plaza by Liz Lemon's great grand daughter
In Jaga Jazzist's Animated Music Video for "Animal Chin", the band travels in two ordinary-looking cars, which bounce wildly on the ground before inexplicably taking to the skies.
Calvin And Hobbes: In one Sunday comic, Calvin daydreams that his parents let him drive the family car. He then makes the car fly simply by driving so fast that the speedometer breaks.
Shadowrun has a selection of hovercars in addition to normal cars, helicopters, and airplanes. The really fun thing is that if you have a reasonable DM, it is possible to afford a hovercar at character creation (it will eat up around half your cash, though)
Teenagers from Outer Space has spacesters: look like a car, move like a flying saucer. No teenager can afford to buy one — but a clever human/alien pair can build one by, yes, cannibalizing parts from a car and a flying saucer.
Flying cars exist in Aberrant, but their use is restricted to police, emergency services and the military.
Flying cars are fairly common on Mars (lower gravity) and Venus (inhospitable surface) in Eclipse Phase.
Dribble and Spitz's taxi in the Wario Ware series is capable of flight and space travel.
The intro of Star Ocean: Till the End of Time depicts a future Earth full of flying cars and floating buildings. They've even put the Statue of Liberty on top of a tower, presumably so New Yorkers can see it better from their flying cars.
John takes his dad's car, and does the windy thing to make it fly in Homestuck.
In Transformers Cybertron, Optimus' vehicle mode has a flight configuration. The side panels swing out and then rotate down to become large wings, and the ladder/cannon on either one swings around so that it still faces forward. His vehicle mode? A fire truck. That's right, he turns into a flying fire truck.
Bob's car in ReBoot is a flying car, which tends to break down and drop like a stone.
Due to being tricked out by her twin super genius brothers, Kim Possible's car has this capability.
As pointed out at the top of the page, flying cars have been invented in Real Life. The idea has just never managed to get off the ground [pun intended] because the flying cars used up way too much fuel while airborne. Also, they had a nasty tendency to crash when they ran out (which happened much more quickly than one might think). Add expense, complexity of operation, and the relative practicality of an automobile as transportation and just taking a general airliner when flight is necessary, and you see the problem.
The critical problem with 'flying cars' is that they are aircraft. As such you can't fly one without a pilot's license, and air traffic control would go insane trying to sort out millions of aircraft flying around each other in a small area. Most existing 'flying cars' are better described as roadable aircraft. Most small airfields are in rural areas, so you have the minor problem of arriving at an airfield and having no transport to the nearest town, except for a taxi or folding bicycle. The idea is that you could detach the wings and propeller, then drive the remaining vehicle by road into town. They are not really designed as a replacement for your normal car.
Not to mention that traffic collisions are bad enough with how cars are now. Imagine how much worse they'd get if you factored in the fact that the car's going to be falling from 30+ feet above the ground.
Not forgetting that he actually created a flying caravan by combining it with a blimp. Okay it isn't technically a car, it drifted into the airspace of an airport (and path of incoming aircraft), and he didn't get anywhere near where he wanted to go...but at least he threw his hat over the wall.
The Moller website does have some lovely quotes, though:
You've always known it was just a matter of time before the world demanded some kind of flying machine which would replace the automobile. [...] No matter how you look at it the automobile is only an interim step on our evolutionary path to independence from gravity. That's all it will ever be.
Of course making it fly safely is only the first step, you then have to get FAA approval and find backing. the Taylor Aerocar managed the second step, but not quite the third.
The closest Real Life equivalent to the flying car of science fiction is the helicopter. Unfortunately, they're expensive, hard to fly, and make much more noise than you would want to live next to, which is why the average person doesn't own one.
The good news is that we now have computers that can make helicopters significantly easier to fly. Of course that doesn't help the noise, and actually makes them *more* expensive... so...
Actually, if one doesn't mind a little less fuel efficiency there's always tip-jet powered helicopters, whose rotor blades are not powered by a central shaft, but instead a jet at the tips. The Nazis tried it using ramjets at the end, but it's less complicated and safer to use compressed air pumped through the rotor assembly by a compressor inside the body. Not only is this system quieter, but the lack of a torqued shaft removes the need for a tail rotor and dramatically decreases the slow response time of control inputs, making it much easier to fly than traditional helicopters.
Small airplanes, such as those made by Cessna, are also pretty close to the science fiction conception of flying airplanes cars in everything but ease of control and appearance. Also, they are very expensive.
A used, very basic Cessna might cost about the same as a (new, good, but not luxury-level) automobile. Learning to fly it and getting a license to do so is probably a bigger difficulty, and many would be averse to the risk to begin with. Then there's additional maintenance costs and complications. And a small plane simply isn't as practical as an automobile for transportation, which is probably the biggest reason why it can't be treated as an equivalent. You can't exactly take a Cessna on a grocery shopping trip, and even for, say, visiting out-of-town relatives, you'll need some way to get from the airstrip to their front door. Of course, part of the reason cars are so comparatively practical is that we have an entire infrastructure designed around them... But it's hard to imagine doing the same for conventional airplanes.
The ParaJet SkyCar is an unusually simple example. It looks like a dune buggy with a parawing and a propeller strapped to the back. Largely because that's exactly what it is. But it works! As a bonus, if the engine fails or runs out of fuel, the buggy will simply glide to the ground with its "wing" acting as a parachute, rather than suffer a deadly crash. Judging from the design, the main purpose will be fun and recreation. Shipping is expected to start this year (2010) — it remains to be seen whether this will turn out to be Vaporware or not.
Urban Aeronautics' proposed VTOL aircraft certainly looks like a large flying car, though flying cars is not what the company intends to create (they want to build aircraft useful for rescue operations, and other non-personal uses). However, the goal is to build a compact, safe, quiet, relatively easy-to-control aircraft that is capable of operating in an urban environment, including safely manoeuvring between buildings while dealing with turbulence, and is capable of remaining airborne while in contact with a physical object (like, say, the side of a building). It certainly sounds like the company may inadvertently take a big step towards creating working flying cars if they succeed. Currently they have a scale prototype undergoing extensive flight testing.
Boeing sunk six million dollars into something called the "Sky Commuter" program in the 1980s. This prototype, which was apparently sold on Ebay in 2008, is all that remains. It looks beautiful, and very much like a proper science fiction flying car, but it seems it did not fly particularly well.
This lot look like they might be close to actually selling transforming flying cars commercially. Hope you have $200,000 on you, though.
This highlights an interesting, if subtle, distinction between "flying cars" and "road-able aircraft", which is a term you'll often read if studying this topic. The Terrafugia "Transition" is an airplane that happens to have compact, folding wings and the ability to drive on regular roads. You still need to take off and land at an airport, and fly the vehicle like any small plane — but you can drive it home from the airstrip after you land, too, as if it were a car. (You can also drive instead of flying if weather conditions are bad). Not quite as glamorous as a full flying car might be — but in the end, far more practical.
While other flying car designs are more like "airplanes you can drive on the road", this I-TEC design is more like "a car that can also fly". It only gets 40 MPH in the air, but it's pretty speedy on the road (see around 2:50 in the video), and the company seems to have serious plans for what they want to do with it.
Volkswagen's China branch appears to have come up with a floating car. This particular concept car relies on magnetic levitation instead of conventional engines, meaning it'll require a lot of specialized infrastructure to be drivable.
Hovecrafts, technically. Well, they don't actually touch the ground when in motion. It happens that their flight ceiling is about an inch.