The United States Army Air Corps was the aviation division of the United States Army in the early 20th century. As atmospheric flight became more advanced, the Air Corps became a separate military branch, the US Air Force.
In July, 1947, the Air Corps retrieved a Ferengi shuttle which had crash-landed in Roswell, New Mexico, after the shuttle had traveled back in time from the year 2372 via time warp. Air Corps general Rex Denning oversaw the interrogation of the vessel's three inhabitants, whom he believed to be alien invaders. The three Ferengi were eventually able to escape with the assistance of two helpful Humans, retrieve their ship, and return to their own time by recreating the time warp. The Air Corps subsequently covered up the incident, issuing an official statement claiming that only a weather balloon had been recovered in Roswell. (DS9: "Little Green Men")