Other mistake: As they travail to The Pentagon in Washington, Carol and Dr. Marvin sit in the exact same mock-up of an airplane's interior that we saw earlier in the movie when a UFO passes in front of it. (00:00:45 - 00:27:00)
Earth vs. the Flying Saucers (1956)
1 other mistake
Directed by: Fred F. Sears
Starring: Hugh Marlowe, Donald Curtis, Joan Taylor, Morris Ankrum
Factual error: The aliens request a meeting with Dr. Marvin on the shores of the Chesapeake Bay, near Washington DC. However, the shot of him driving along the shore line shows mountains in the background, which don't exist in Eastern Maryland. (00:35:13)
Dr. Russell Marvin: Both Carol and I are subject to the same atmospheric disturbances that may have affected other observers, but there is a qualitative difference, when you're a scientist.
Trivia: Paul Frees is the apparent "spokesperson" for the aliens. His voice is heard throughout the movie. He's also the voice visitors hear in "The Haunted Mansion" rides at the Disney parks.