The main character is based on Arch Hall Sr., director and star of films such as Eegah (1962) and Wild Guitar (1962), and was an Army buddy of the film's writer. Hall was indeed a pilot, as is his son, Arch Hall Jr. Hall was aware his friend Bowers was writing the script and was flattered and pleased. Once the film was completed and in release, Hall sued the producers of this movie for invasion of privacy. The suit was apparently dropped or settled out of court. Bowers, writing later about his friend and the incident, not only bore Hall no malice, he thought Hall's actions were consistently in character for the sharpie with whom he'd served in uniform.
The Civilian Pilot Training Program they were a part of was a real program started just prior to WW-II, although it was phased out in the summer of 1944. A number of famous pilots received their flight training through the CPTP.
Private Bowers makes the (voice over) comment, "And that's when the Vigaro hit the Mixmaster." At the time of the story, Vigaro was a brand of steer manure, and a Mixmaster was a brand of electric kitchen mixer for mixing cake batter.