Other mistake: Before Becky and Miles go down the steps after leaving his office she says "I've been in Reno". The camera goes totally out of focus for a second right when she says, "Reno" the second time. (00:07:10)
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)
Other mistake: When the title card is shown, the copyright year is shown as 'MCMXXXIV' (1934). It was released in 1956 (MCMLVI).