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)
Carol Marvin: My father! What have you done to him?
Alien: You're addressing General Hanley's mind, not General Hanley.