I had a youthful fascination with planes, rockets, gliders, helicopters and just about everything else that flew. Books helped fuel this interest, including Pilot Jack Knight and Reach for the Sky, Paul Brickhill’s biography of Douglas Bader. He was the English First World War pilot who lost both legs in a crash, yet still served in the Battle of Britain as a fighter pilot. What I may not have mentioned before was that my obsession with flight actually extended a little beyond paper airplanes and 50-cent balsa wood gliders. Back in the 1970s, the fledgling sport of hang-gliding was dominated by the familiar, triangular gull-winged glider. Never quite content with the conventional, at the tender age of 12 a classmate and I decided we should shake up hang-gliding with a new model. Yes,...