OSHKOSH, Wisconsin – There's a moment in every flight where gravity cedes control to Yves Rossy and for a few minutes he flies as birds do, with only a wing on his back and the wind at his face. Sure, there are jet engines, but he hears mostly the wind. It's perhaps the greatest feeling of freedom one can experience, and after all these years, it never gets old.

"That is one of the best moments, this pass from vertical to flying," he says. "I am flying. I am not falling anymore, I am flying."

The 54-year-old pilot, known worldwide as Jetman, flies with nothing more than a carbon fiber wing and four tiny jet engines strapped to his back. He’s been doing it for years – he’s flown over the English Channel and across the Grand Canyon, among other things – and videos of his feats are easily found on YouTube, but you just can’t appreciate how amazing it is until you’ve seen it in person.

Rossy all but stole the show here at Airventure in Oshkosh when he flew in formation with a Boeing B-17, the famous World War II “Flying Fortress.” WIRED was among those invited to ride along, and to see Rossy turning his head and shoulders to fly in formation alongside the B-17 was simply incredible. And we weren't the only ones impressed.

"The perspective of seeing a guy off your wing, with a wing on his back — there’s just nothing to prepare you for it," said B-17 pilot George Daubner. "I don’t think any of us expected the maneuverability he had."

Rossy flies with the grace of an eagle, and the subtle body movements he uses to maintain flight – and perform his loops, rolls, and other maneuvers – mimics a bird of prey.

The former Swiss Air Force pilot has flown everything from sailplanes to fighter jets. Before becoming Jetman full-time four years ago, Rossy was a captian flying the Airbus A320 for Swiss International Air Lines. But he always dreamed of a more freeform way of flying. He’d been skydiving, but that wasn’t quite what he was looking for.

The idea of flying a wing strapped to his back began in 1993. The first step was to simply glide. To start, he strapped on a custom built inflatable wing and learned how to glide. Once he had the basics of that figured out, he built a rigid carbon fiber, kevlar reinforced wing and added a pair of tiny jet engines. That was the breakthrough that allowed him to make level flight.

"It was totally crazy," he says of that first powered flight. After so many glide flights, the first time he flew straight and true without descending was like having someone pulling a giant handle on his back he says, "I can remember it very well, because it was so not normal."

His wing has evolved over the years. He's built more than a dozen and has destroyed a few. Though in an emergency, he can drop away from it during flight, and the wing has its own parachute.

Today he continues to fly with a carbon fiber wing that has a two meter (~6.5 feet) and weighs 55 kilograms (121 pounds) when fully loaded with jet fuel. The four engines produce roughly 50 pounds of thrust each. To fly in the United States he had to register himself and his wing as an aircraft, N15YR is his identification number. He says he received an exemption for flying without a seat belt.

His flights have similarly evolved. Early on he had a few close calls, losing control in a spin and another incident with uncontrollable oscillations. Today he's capable of aerobatics and close formation flying, something he’s done with the Breitling jet demonstration team, a Douglas DC-3, a British Spitfire, and now the Boeing B-17. And all of the flight control is done with body movement. There are no ailerons or other flight control surfaces. The four engines are mounted beneath the wing; eight gallons of jet fuel provide about 10 minutes of thrust. The only instruments are an altimeter and a timer mounted on his chest. The timer is his fuel gauge. The throttle control is a small dial mounted to a strap wrapped around his index and middle finger on his right hand.

Photo: Shore/Breitling Mike Shore

Rossy performs a thorough pre-flight check with a crew chief who helps ensure the four engines are ready to go. The size of the wing keeps Rossy from actually getting inside an airplane or helicopter, so Rossy stands on the skid as it carries him to altitude. Less than a minute before getting to the proper altitude – 6,500 feet here in Oshkosh – Rossy and his assistant start the engines.

"I give an input on my little throttle, and that gives an electronic input to the engines for the startup process," Rossy says. "Normally after 30-35 seconds all four engines are stabilized at idle with four green lights."

Once the engines are running properly, the crew chief disconnects the monitoring equipment from the engines, Rossy makes a visual check to get his bearings, and then he drops into the void.

"I let go backwards," he says of the backflip he makes away from the skid. "When I let go backwards, I give one turn of the throttle. There is a spool up of the engines and I am looking for speed."

With only an altimeter and timer, Rossy uses his skin and ears as airspeed indicators.

"You feel very well, you feel the pressure," he says touching his face and torso as he explains how the air feels during the flight. "You just have to wake up these senses. Inside an airplane we delegate that to instruments. So we are not awake with our body."

As he freefalls, Rossy builds up extra speed as he flies nearly straight down to improve his control. Tests have shown he’s going about 160 mph during his descent. Once he feels he’s at the proper airspeed, it’s time to start flying.

"That’s the really good part," he says.

At full thrust going almost straight down, Rossy raises his head and arches his back, shifting the airflow and transitioning him to horizontal flight. He describes flying his jet-powered wing with awed amazement of someone who still can’t believe he’s doing it.

"I am at full thrust, I arch, and lift is created on my wing and holds me in the air."

Once in horizontal flight, Rossy can relax his head and back to fly straight and level. The throttle dial needs about two turns to go from idle to full power, and he’s typically at about 80 percent. That’s good for around 110 mph. Small changes in thrust allow him to fine-tune his position, something he must do when flying in formation with other aircraft.

Like, say, a B-17.

Photo: Bruno Brokken/Breitling Mike Shore

For his final practice flight before performing over Oshkosh, the big Boeing was in a constant turn at 110 mph. Rossy dropped from the helicopter and ended up several hundred feet below the airplane, but within seconds was at the same altitude. Peering at him through the clear dome on top of the airplane that once held a gunner, your first reaction is simply to laugh as Rossy takes his place off the right wing. Here we are at 5,000 feet, doing 110, alongside a guy with his arms and legs dangling beneath a wing strapped to his back.

I have to admit, I was a bit skeptical of the whole show. After following all kinds of aviation for many years, including Rossy’s exploits since he first started flying, I didn’t quite know what to think about seeing the Jetman in action. But once I saw it, all I could do was laugh in disbelief. Rossy flew all around us, passing underneath as he pulled up near the bomb bay doors, flying from the left wing to the right. He even backed off a few hundred feet to perform aerobatics. And he describes all of it with a continued sense of amazement, but at the same time as if he were just another aircraft.

"A roll is twist the shoulders," he says making the simple motion in his chair, "and a little bit hands where you want to turn, like a ski jumper."

Rossy says the movements are completely intuitive, "I can’t tell you what I’m thinking." He compares it to skiing: Apply a little pressure here, a little pressure there and adjust your movements as needed.

Loops however are a bit more complicated. He has to enter the loop at more than 180 miles per hour.

"It’s full speed and you feel it. It’s like the sound barrier," he says shaking around to show the buffeting of flying at top speed. "Okay, it doesn’t go faster than that, then arch, about the 3Gs, then it’s physical. You have to hold the arch."

The biggest challenge comes at the top of the loop. As the airspeed slows down over the top, Rossy must reduce thrust to avoid getting in trouble.

"If not I have a pitch up moment and I’ll tumble," he says, "that was my first looping experience, the tumbling."

Rossy says he tumbled five or six times during the first attempt, and since then he has learned how to use his arms to change his center of gravity, helping to finish the loop (see video below).

Except for the top of a loop, most of the time Rossy keeps his arms at his side during flight – though during his formation flight with the B-17 he did extend his arms while flying level. He was just having fun.

"It was just to play superman," he says laughing and humming the theme song to the movie with his arms stretched out again.

Photo: Jason Paur/Wired.com

One of the more impressive aspects of Rossy’s flight is how quickly he can speed up and slow down during flight, "I have bad aerodynamics," he says. "I am flying drag. As soon as I don’t have power, it brakes. When I give it power, it reacts."

When the fuel timer approaches 9 minutes, 45 seconds, Rossy prepares to pull the ‘chute. Once he is lined up where he needs to be, he eases off the throttle to put the nose down. Then he cuts the engine, resulting in a bit more dive. When the engines are off, Rossy opens the parachute and begins his descent.

With nearly 100 pounds on his back, Rossy says he only attempts standing landings when the wind is at least 15 mph so he can come down vertically. Otherwise it’s a six point landing, "I brake maximum," he says referring to the lines on the parachute, "then feet, then knees, then hands."

At age 54, Rossy knows he probably won’t flying as Jetman forever. He already has his first student, a three time world champion skydiver who made his first powered flight earlier this month. Rossy says various militaries and other organizations have approached him about developing a jet wing for special forces, but for now he’s concentrating on his own flying and continues to explore the skies as Jetman, flying as birds do, and as we all wish we could.