Continuity mistake: In a scene in a town on the rooftops as the British fight the Nazis, we see that the townsfolk were truly ahead of their times as they nearly all have television antennas.
Continuity mistake: After the scene where a British soldier is killed trying to recover supplies, a C-47 is seen crashing with a smoking engine. After the crash, look carefully at the explosion and you can see the airplane winging away.
Continuity mistake: When they're building the Bailey bridge to replace the destroyed Son bridge, work continues into the night. Cut to scene of a soldier waiting for them to complete the bridge - in daylight. Cut back to the continuing work on the bridge - it's dark again.
Continuity mistake: Halfway through the movie, James Caan drives his jeep to escape Nazi brigades and brings his wounded comrade to the hospital. He is wearing full dress, with jacket. After he holds the doctor at gunpoint to "check" his friend, the scene switches outside where he is smoking a cigarette without the jacket, then flashes back with him wearing the jacket. (01:41:00)
Chosen answer: The Germans did use some Hitler youth movement in the war.