“Where’s my jet pack, dude?” is a common whine about how supposedly disappointing 21st-century technology is turning out to be.

No matter that we all carry a pocket communicator/computer/library beyond the imagining of any 20th-century science-fiction writer; our real yearning, it seems, is a more ancient one: to fly like Icarus, who in Greek mythology flew—and crashed—using wings made of feathers and wax.

Funny thing is, though, the jet packs that comic books and movies have envisioned for almost a century are now here.

If you care to pay $4,950 for a day-long session to JetPack Aviation in Van Nuys, California, the Icarus experience is yours for the taking, minus the crashing bit. In Salisbury, England, Gravity Industries will do the same for $9,300, or $2,500 for a taster. Both companies will sell approved clients their own jet pack for between $350,000 and $450,000.

Flying strapped to a jet pack is even legal in most countries. Well, not il-legal. Yet. Bureaucrats, faced with the “Is it a bird? Is it a plane?” question, can’t figure out a definition for a jet-pack-borne human. And since there are barely any in the skies, it’s not yet a pressing problem.

A distorted photomontage of a man wearing a jet pack flying above the Unisphere, at the 1964 World’s Fair, in New York City.

So, just as you could once fly drones anywhere, as yet there’s nothing specific to stop you from firing up your jet pack like Iron Man and buzzing the White House or Buckingham Palace—even if in reality the guards may just shoot first and argue legal points afterward.

Jet packs that kind of work are not new. One among many in the 1950s and 1960s was designed by Bell Aerosystems. Most of its power was expended lifting the several gallons of fuel it needed in order to stay up, so it could fly for a maximum of only 21 seconds.

Flying strapped to a jet pack is even legal in most countries. Well, not il-legal. Yet.

But the Bell Rocket Belt was impressive enough by 1961 to be demonstrated to President Kennedy. It went on to appear in Thunderball, the 1965 James Bond film, and later at the opening ceremony of the 1984 Los Angeles Olympics.

But only in the past three or four years have jet packs been able to stay aloft long enough to make this kind of personal flying viable, either for fun or as a practical method for things like mountain rescue.

The technology that has given you your jet pack, dude, has come from an unlikely source—not NASA or the military but small companies making jet engines for radio-controlled-model-airplane hobbyists, often retirees from aviation and engineering.

It’s not widely known that, around the world, there are extreme model fliers remotely piloting jet planes at speeds in the hundreds of miles per hour. They use mini jet engines, made mostly in the U.S., Germany, and China and selling typically from around $2,000.

Both Gravity and JetPack—the leading pioneers in the be-your-own-bird business—use four or five such model jet engines, which are strapped directly onto various parts of the flier’s body and—crucially—need only a couple of gallons of jet fuel or diesel per four minutes or so in the air. The next development, they say, will be electric motors with an even better power-to-weight ratio, and they’ll be quiet, which even mini jet engines are definitely not.

What’s it like putting your dreams of flying like a bird into action and firing up a jet pack?

Sean Connery as James Bond in Thunderball, 1965.

Richard Browning, Gravity’s founder, a former oil trader and Royal Marines reservist, is eloquent on the sensations of being his own airplane, flying at up to 85 m.p.h. and 120 feet in the air.

“You hold your arms out, you squeeze that trigger, you lower your arms down, you feel the weight come off your feet, gradually, gradually until the ground disappears. And suddenly, despite being at the core of all that fury, it goes peaceful. You just think about where you want to go, and go there. In a sexier way, it’s a bit like a bicycle, but in three dimensions. It’s effortless and sort of free. You just go where your consciousness takes you.”

Fliers literally aim their body toward the point they want to reach, while they regulate their height with a process called thrust vectoring: point both arms down and you go up; flare your arms out to the side and you sink.

Although there have been three deaths of aircraft-less aviators in less than three years—a French stuntman, Vincent Reffet, in Dubai; a British space scientist, Angelo Grubišić, in Saudi Arabia; and his flying pal, Robert Haggarty, in Italy—Browning points out that the fatalities have been of wing-suited, jet-propelled daredevils base-jumping or dropped at high speed from aircraft.

The Gravity and JetPack Aviation style of jet pack, by contrast, flies low and slow, and safely—so far.

How useful jet-pack flying might be is another matter. Isaac Asimov predicted that jet packs would one day be “as common as a bicycle,” but aerospace engineer Mike Hirschberg, executive director of the Virginia-based Vertical Flight Society, is skeptical.

Hirschberg speaks for engineers involved with helicopters and vertical-takeoff planes, and is respectful toward flying-car concepts.

But jet packs, not so much. “I mean, they’re really cool and fun and great for demonstrations and stunts and viral marketing and things like that, but they’re not practical for any kind of transportation or commercial applications. It’s sort of a solution in need of a problem.”

The chance of there being somebody suited up, trained, and available to swoop up a mountain on short notice, Hirschberg argues, is just too remote.

More than 500 people worldwide, however, have been rescued from various perils by drones, the drone-maker DJI announced recently.

So, even though jet packs are here, our perception of them is likely to remain as something more in the realm of entertainment than commuting.

Which may explain an exchange in August between an air-traffic controller at Los Angeles International Airport and an American Airlines pilot approaching at 3,000 feet.

“Tower, American 1997,” radioed the pilot, “we just passed a guy in a jet pack.”

“Only in L.A.” came the reply from the control tower, with a slight sigh.

The incident, as with a similar one six weeks later involving a China Airlines flight into LAX, has yet to be explained. Too high for a jet pack, the sighting may, according to one theory, have been a drone dangling an inflatable astronaut.

Unless it was Iron Man.

Jonathan Margolis is a London-based writer