George Takes the Air (1938)

Accident-prone George Brown (George Formby) is rejected by the Home Guard because he can't tell his left from his right. However, when a pal in the RAF forgets some very important documents George dons a uniform and takes them to the base, where he is mistaken for a dispatch rider. George soon finds it is easier to get into the air force than it is to get out, but finds some compensation when he meets his Sergeant Major's pretty daughter.