Have you people ever heard of Die Glocke? The classical idea of Nazi flying saucers is actually founded in reality.
Pope Pius XII attempted to perform “remote exorcisms” on Hitler during WWII, believing him to be possessed. During WWII, Admiral Dönitz claimed “The German submarine fleet is proud of having built an invisible fortification for the Führer, anywhere in the world.” During the Nuremberg Trials, He spoke of “an invisible fortification, in midst of the eternal ice.”
Don’t go accusing the film of being unrealistic, there’s plenty of conspiracy theories surrounding the Nazis.