The idea for this episode was probably based on the activity of a real Japanese pilot during World War II who would harass the U.S. Marines on Guadalcanal. This pilot would fly over Marine encampments at night in order to deprive them of much needed sleep. Sometime he would drop a bomb, other times he would just fly over them. The Marines nicknamed him Washing-machine Charlie, and like 5 O'Clock Charlie, his plane's engine was out of timing.
The airplane was a Ryan PT-22, flown by its owner, Don Burkett, hidden in the rear seat. It was painted with a North Korean color scheme for this episode.
Five O'clock Charlie marks the first appearance of Jeff Maxwell, who played semi-regular Private Igor Straminsky.
At one point Frank says: "Nobody bet on the Battle of Britain! 'He who controls the skies, controls the war.' Hermann Göring said that.", to which Henry replies, "He also wore tutus and ate whole bakeries, Frank". Hermann Göring (1893-1946) was one of the most powerful people in the Nazi Party, second to Adolf Hitler, leading up to and during World War II. While Göring was obese and loved food, there is no record of him ever wearing a tutu, although he did prefer lavish and garish clothing, which the people of Germany mocked him for.