Note The truth about United States certificated scheduled air transportation today. Air Transport Association of America, circa 1953/54. Hayward, Donald W. Study of aircraft in short-haul transportation systems for 1985. AIAA Paper No. 67-771. American Institute of Aeronautics and Astronautics, AIAA 4th Annual Meeting and Technical Display, Anaheim, California, 23-27 October 1967. ...