Trapnell reportedly had "a natural flying ability" and "a firm grasp of aerodynamics." While at Pensacola, he flew in a variety of aircraft, gaining significant experience and further honing his skills. In 1930, he was transferred to
Naval Air Station Anacostia in
Washington, D.C. In June of that year, along with two other pilots, he was assigned to a new unit, the
Three Flying Fish, the Navy's first official aerial demonstration team. Flying specially modified
Curtiss F6C-4 biplanes, they traveled around the nation performing intricate, aerobatic exhibitions. The team was disbanded in April 1931, and Trapnell was soon assigned to the small plane unit attached to the Navy's
dirigible airfleet. From 1932 to 1934, he served on the airship at
Naval Air Station Lakehurst in New Jersey and her sister, at
Naval Air Station Sunnyvale,
California. At the latter installation, he was responsible for re-engineering the apparatus for hooking up aircraft while in flight as well as a rewriting the procedure. In 1938,
Lt. Trapnell flew in a squadron of eighteen bombers from
San Diego,
California, to
Honolulu,
Hawaii, in what was "the greatest over-ocean formation flight" to date.
LCDR Trapnell returned to Anacostia in 1942 as the chief of the Test Flight Section. Two years later, and with promotion to
commander, he relocated with the section to the new
Naval Air Test Center in Maryland. With
World War II raging, Trapnell dedicated himself to redesigning flight testing and procedures. He initiated a series of lectures and classes to familiarize pilots not only with the rudiments of flying but to learn the intimate details of flight engineering, performance, stability, and control. He required that the aviator know every aspect of his aircraft under all conditions. So respected was Trapnell's knowledge and ability that, in 1942, he was personally requested by
Roy Grumman to evaluate the new Grumman
F6F Hellcat, the Navy's answer to the lethal Japanese
Zero. Circumventing the usual testing procedures, Grumman had Trapnell take the fighter on a crash program. "He came to the factory and flew the prototype F6F. It suited him, as I remember, except for the longitudinal stabilityhe wanted more of that. We built it in and rushed into production without a Navy certificate on the model. We relied on Trapnell's opinion. His test flight took less than three hours. I'm not sure we ever got an official OK on the Hellcat design." 1943 saw Trapnell on temporary duty assignment at the
Muroc Army Air Field in
California for secret testing. On April 21, he became the first naval aviator to pilot a jet aircraft, the
Bell XP-59A Airacomet, the first such plane built in the United States. Shortly thereafter, he was promoted to
captain. For the remainder of the war Trapnell served in the fleet, commanding two squadrons and an escort carrier. In October 1944, he became chief of staff to
RADM Arthur Radford, Commander
Carrier Division Six, overseeing the remaining air strikes and amphibious landings in the
Pacific theater. ==Naval Test Pilot School==