When Benson and Heathcliff's plane lands, it is without landing gear in an area where no planes are near. When Heathcliff gets out of the plane, it is upright, indicating that landing gear is present, and other planes surround theirs.
In the montage of Army Air Corps airplanes shown near the end of the film there were two types that were already obsolete by 1941: the twin-engine Martin B-10 and the Boeing P-26. Both of these planes were no longer in operational squadrons and had been relegated to "hack" duties or service overseas in the Philippines or the Canal Zone. The Douglas A-17s were obsolescent and on their way out too. Only the four-engine Boeing B-17 was in first-line service at the time.
After Bud and Lou are riding that runaway torpedo and are thrown off and the torpedo
explodes demolishing a barn, Bud refers to Lou as Herbie. Lou's name is Heathcliff in
this film, he was Herbie Brown in Buck Privates.