At the dance, every girl from Mrs. Shackleford's academy who we see sitting in a chair has her hair hanging over half of her face in a parody of the hair style of Veronica Lake, but when we see them dancing, none of them is wearing her hair this way.
When Pamela arrives at the stopped train, she is directed left to the train car in which Major Kirby has a compartment. However, when she returns to her car which hasn't moved, she approaches it from the right, the opposite direction of Kirby's train car.
The external view of the outside of Lucy Hill's house there is a six-panel front entrance door with a large brass door knocker, but when they move to the inside of the house that six-panel front entrance door is incorrectly missing the large brass door knocker. Seen early in the movie 37:28 to 37:34 and again seen 78:03 to 78:07.
In the train station she swipes a light colored(yellow or white?) balloon to help her in her disguise as a child under 12; once she is seated on the train the balloon is much darker (red?). When she stands as the conductors are questioning her the balloon is lighter, but when she sits down and the guy next to her pops the balloon it is dark again.
Susan arrives at New York City's Grand Central Terminal and attempts to buy a fare from a New York Central Railroad ticket clerk. When she eventually has a ticket and is on the train, the exterior view is of a Pennsylvania Railroad train pulled by streamlined steam locomotive. That train would have departed from New York's Pennsylvania Station.
The cadet left the switchboard to get a radio, and returned with a battery portable valve radio. Although quite expensive to buy and to operate, there was a very large market for battery portable valve radios and they were very common throughout the valve era. Batteries were the only possible power supply, because valves with "heaters" used with AC mains power electricity appeared after the D.C. battery types. Texas Instruments in 1952 demonstrated their all-transistor AM radios, but their performance was well below that of equivalent battery tube models. In August 1953 a workable all-transistor radio was demonstrated at the Düsseldorf Radio Fair by the German firm Intermetall. If you had no knowledge of the existence of battery portable valve radios in 1942, you might mistakenly believe that the portable radio is a fake, because the portable transistor radio was not invented till 1952.