Continuity mistake: As the aliens announce their intentions to the people of earth Dr. Marvin walks up to a radio in the back of the lab and says, "If I'm right they'll sail into Washington in broad daylight ". If you look closely the radio is pointing to a different station that it was when we saw it previously in the scene even though no one has gone near it. (01:04:35)
Continuity mistake: At sky hook the soldiers pull up in a jeep and jump out carrying M1 carbines. In the next shot when they lay on the ground to fire at the aliens they are armed with M1 Garands.