In the 1970s a group of California visionaries developed an interest in lightweight, low-powered machines. Scientist and engineer, Paul MacCready, pulled them together to build a plane capable of winning a long-standing prize for human powered flight. Their other successes included a man-powered plane, a solar powered plane, a solar-powered car, an 18-foot flapping wing flying replica of a pterodactyl for a Smithsonian-sponsored IMAX film, and a high-altitude...