[Looking for title of wwII prison excape movie]

I looked up the movie The Birdmen and it is the movie that I was trying to find. Thank You for your help, with out it I still would not know the title of this movie.

[Looking for title of wwII prison excape movie]

In the movie that I am looking for the german prison is in a castle high up on a cliff. to excape over the wall would be to drop to your death. the prisoners build small gliders and throw them over the wall for enterainment and to learn how to build a glider large enough to carrie a couple of them to freedom. They build their large gilder, while hiding it from the germans, and finally launch it using a bath tub as a counter weight, allowing a couple of prisoners to excape.