Boom in the Moon (1946)

In the final days of WWII, an earnest but somewhat dense sailor (played by Keaton) is lost at sea. Months later, he makes a landing, but, not realizing that the war is over and thinking that he is in Japan, he surrenders to Mexican police, who mistake him for a serial killer. Thrown in a jail cell with an American thug, he is to be hanged next morning, when suddenly a rocket scientist offers him and his cellmate a chance to avoid execution if they pilot an experimental atomic rocket to the Moon. Once you get past the horrible dubbing of this film you can enjoy some wonderful moments with Keaton and some great sight gags.