Daedalus by Robert G. Williscroft

Using a new Gryphon-7 hard-shell wingsuit, Tiger Baily, irreverent member of the Navy SEALS Winged Insertion Command, makes a harrowing first experimental base jump from the edge of Space, the Fred Noonan Skyport 80,000 meters above Jarvis Island in the Equatorial Pacific. Tiger’s target, which he must reach to survive, is Kiritimati Island, a tiny isolated atoll 379 km northeast of Jarvis over ever-threatening and oh-so-deep ocean waters.