“The YO-3 Quiet Star was an airplane built by Lockheed on the Schweitzer glider design, capable of carrying two, with an engine, for night reconnaissance missions. It was so quiet that it could fly at 1500 feet and not be heard. It was reported to fly at 200 feet and only be as loud as a bird in flight. Eleven were built, nine deployed. Only one exists today in the Vietnam Helicopter Museum, Concord, California.”