At the top of Notch Peak, a sandstone cliff more than 9,000 feet high in the Utah desert, Mike Swanson wants to get on the ground as quickly as possible: He doesn't like heights. The fastest way down is straight off the edge.
"I'm scared every time, absolutely," said Swanson, 37, a member of the Red Bull Air Force, a team of professional skydivers and BASE jumpers who regularly push the limits of human flight. "But I trust my equipment. I trust my skills."
With a specially designed wingsuit and parachute, Swanson of Truckee, Calif., leaps from the rock face and plunges into the narrow canyon below. Although scared of heights, Swanson loves to fly.
After free falling for a few seconds, his wingsuit, consisting of fabric between the arms and legs, creates lift as he banks to the left, flying through the canyon like a bird.
"The idea of jumping with a wingsuit is it allows you to jump a lot of locations that you wouldn't normally be able to BASE jump," said Jon DeVore, 35, manager and Red Bull Air Force team member who's a Juneau, Alaska, native living in California.
"With the wingsuits on, it slows your descent rate down to 40 to 50 mph compared to a normal BASE jump where you'll be going close to 100, 120 mph. But with a wingsuit you can slow that down so you can have a lot more time on your jump."
These "Birdmen," as they are sometimes called, are not technically flying, despite appearances. Throughout their jumps, they continue to lose altitude, but the lift of the wingsuits creates the sensation of flying for the jumper and the illusion of flying to the observer. It's not actual human flight but perhaps as close as is humanly possible.
"It is the feeling of flying, absolutely," said Miles Daisher, 41, a Red Bull Air Force team member from Twin Falls, Idaho. "When you can control how fast you go down, you can control turning. It's a bit like flying a plane."
The illusion of flight is enhanced by smoke canisters attached to the jumpers' ankles that leave a white streak behind them as they descend, eventually deploying a parachute to land.
"It really adds to the dramatic effect," Swanson said. "When you see the smoke and you see the trail come down, then you really understand the speed and how fast and how far we are moving."
The jumpers of the Red Bull Air Force travel the globe searching for the biggest and most challenging BASE jumps, an acronym for the places from which they jump: buildings, antenna, spans [bridges], earth [cliffs].
Most wingsuit jumping takes place on the rugged peaks of Norway, Switzerland and other parts of Europe where the canyons are deep and the BASE-jumping laws are liberal. Locations conducive to wingsuit jumping are more difficult to find in the United States, with many of the best spots either difficult to access or off limits to jumpers.
"Good Morning America's" Weekend Adventure series followed members of the Red Bull Air Force team to the Utah Desert for their first jump from Notch Peak, a challenging BASE jump even for jumpers with thousands of leaps under their belts.
"Definitely what I call a black diamond BASE jump," DeVore said. "I've never jumped in a canyon like this. After the initial exit it got a little turbulent and bumpy, but then all of a sudden I felt like I just got punched in the stomach with air. It was not nerve-racking but exciting and stimulating."
Red Bull Air Force team members meticulously prepare for each jump, monitoring wind conditions and inspecting the landing area.
"It's all calculated risk when we're out here," Swanson said. "I don't see it as extreme risk. I'm happy doing what I'm doing, I don't think that I'm pushing it more than most things that people participate in life."
Calculating the risk has gotten more complicated for the members of the Red Bull Air Force as they've aged and started having children.
"I actually have tons of hesitation," DeVore said. "I second guess what I'm doing non-stop, but [because of] the passion I have for it I think I'd turn into a really grumpy, angry person if I had to stop doing what I do."
The risks hit home last year when Daisher's best friend, professional skier Shane McConkey, died trying to execute a wingsuit jump while skiing in Italy. McConkey, 39, left behind a wife and a 3½-year-old daughter.
"That crushed me," Daisher said. "It does make you start to rethink things and I did take some time off and back up and think, 'Hey, am I doing the right thing here?'
"But you're here and you get one life; you've got your one quarter and if you're going to stay around and be safe your whole life, then you've never really lived, you're already dead."