The Birdmen (1973)

During WWII an American soldier sent to Norway to help with the escape of a scientist working on the atomic bomb for the Germans. Before they can escape they are captured and sent to a POW prison camp in an alpine castle. Cook must find a way to escape with the scientist before the Gestapo discover the Norwegian's true identity and convinces the other prisoners to build a two person glider in which they plan to escape.