At the start of the film, Carl Becker and Henry Bremmer are traveling at speed in a 1939 Buick. When chased by a cop, who ends up escorting them to the airport, the car has transformed into a 1941 model.
Carl is shown boarding an American Airlines DC-3 at the beginning of the film, but the model shown in flight is a completely different airplane - with a twin tail even.
When Carl is talking to Jim, he tried to get him to move to his hotel. When Carl mentions the hotel's name, it is evidently dubbed over.
The radio operator at the hunting lodge tells Dr. Woodford U-186 is off the coast. Later, Dr. Woodford tells Paula it's U-86 that is going to take them to Germany.