PICTURE CREDITS
Cover—Aerojet-General; 18-21—NASA; 36—General Electric; 37—Westinghouse; 39, 75—USAF; 43 (top)—Reflectone Electronics, (bottom) Ohio State; 46, 47, 49, 50—Kaman Aircraft; 57— Helicab; 59—Mercury Helicopter Services, Inc.; 61—Lockheed; 63—SIPA; 64—Beech; 65— Cessna; 68—Jet Propulsion Laboratory; 69—Air Products & Chemicals; 70—Aerojet-General.