Is it a bird? Is it a plane? Actually, it's a bit of both.
Wingsuits fly for the same reason jets take off and eagles soar.
The suits turn the human body into an "airfoil" -- a curved wing that produces lift by allowing air to flow faster over the wing than under it.
Skydiving photographer Harry Parker caught these incredible images of wingsuiter Rip Cord in action over Sebastian, Florida. And we asked skydiving pioneer Tony Uragallo, founder of TonySuits, to tell us more about how today's wingsuits fly.
[All photos: Courtesy Harry Parker Photography] Harry Parker Photography
The pilot's front wing.
Carbon fiber wingtips extend the wingspan of the suit to increase performance and help control direction and glide angle.
Modern suits have a shaped piece of semi-rigid foam on the leading edge of the wing to smooth the flow of air over the arm.
Suits of the past required serious muscle power required to hold arms out, but increases in the pressure of the inflated arm wing mean today's put less strain on the pilot.
The reduced burden is a luxury for pilots, but is fast becoming a necessity: the longest flights can now top 9 minutes and support from the inflated wing behind is crucial. Harry Parker Photography
Suits are handmade from hard-wearing nylon Parapack. It's the same material that tough luggage is often made out of.
Like traditional aircraft wings, suits are stitched into ribs, which hold the inflated wing in shape.
Each suit is custom-made, with manufacturers cutting and stitching fabrics to a pilot's individual measurements. The result: a top suit can set you back over $1750. Harry Parker Photography
Human flight is all about inflation.
The suit must become rigid to start flying and design development in recent years has meant that suits now inflate much more quickly -- making jumps from lower cliffs possible for the first time.
"Air-locked" vents on the bottom of the suit allow air pressure to build without air escaping and force the suit to take shape. Harry Parker Photography
The rear wing.
This is the second area that is crucial to generating lift.
Stitched with ribs along the length and inflated to greater pressures than before, it is now more rigid than previous suits, making it easier for the pilot to comfortably maintain the squirrel-like flying position.
Top level TonySuit's can now feature a full-length deflector that inflates along the back of the suit, so that air flows smoothly off the parachute. Harry Parker Photography
Parachutes are essential to slow fast-flying pilots down before landing but, packed up, they are hardly the most aerodynamic shape.
Every effort is made to reduce the drag and TonySuits can now enclose the parachute rig and harness within zipped-up areas of the suit. Harry Parker Photography
For BASE jumping -- where pilots often have to climb to precarious mountain edges before a jump -- heavy duty studded rubber pads on the soles of the feet provide extra grip for the wingsuit pilot as he or she prepares to jump. Harry Parker Photography
Zips are a necessary evil that allow the pilot to free themselves from the suit's restrictive grasp after pulling the parachute cord -- but they also contribute to drag.
Modern designs attempt to limit the resistance caused by zips and seems, to increase the speed and gliding distance of the suit.
The newest Tonysuits' models feature just two long zips which follow the line of the body. Harry Parker Photography