Continuity mistake: Maj. Huglin walks into the lab as Dr. Marvin works on the high frequency ultrasonic gun and all the equipment behind them is lit up. In the next shot it's not. (00:47:40)
Continuity mistake: Several authentic looking prop newspapers have headlines reading that "Operation Sky Hook has been wiped out" and they all have the same mistake, no date on top. (00:26:40)
Continuity mistake: Dr. Marvin tries out his high frequency ultrasonic gun in front of Maj. Huglin. Before he fires it the device is moving, than in the next shot it's still. (00:47:05)
Continuity mistake: Dr. Marvin tries out his new improved magnetic interference unit and an alien craft is spotted flying around inside of the Belmont lab above their heads. Before the craft takes a dip down at them they're standing on the right of Dr. Marvin's magnetic device, but when we see them again they're standing on the left of his device. (00:50:20)
Continuity mistake: As Dr. Marvin tries out his high frequency ultrasonic gun in front of Maj. Huglin they're all staring at it. In the next shot they're looking at the cement block before it's destroyed. (00:47:05)
Continuity mistake: Dr. Marvin walks in as Carol sleeps in their hotel room and then proceeds to call the aliens on his shortwave radio. By the time he walks out of the room to meet with them by the Chesapeake Bay the items on top of his dresser have moved, without anyone going near them. (00:31:10)
Continuity mistake: Dr. Marvin tries out the new improved magnetic interference unit and invites Prof. Kanter to be the first one to shoot it. He walks over to Prof. Kanter standing in front of the gun twice between shots. (00:49:30)
Continuity mistake: As Dr. Marvin tries out his high frequency ultrasonic gun in front of Maj. Huglin the engineer to the right of them turns on the generator. In the next shot the lighting has changed and the the shadow of Dr. Marvin's head appears on the pillar behind him. (00:47:00)
Continuity mistake: At the Pentagon Carol and Dr. Marvin speak to the generals and one of them holds a pipe in his right hand. In the next shot he's holding the pipe in both hands. (00:46:15)
Continuity mistake: Carol and Dr. Marvin are locked in the underground bunker at "Operation Sky Hook" as the power goes totally dead. Somehow in total darkness without any power we still hear the sound of the aliens speaking which is strange because if you look at the tape recorder it's not running at all. (00:24:40)
Continuity mistake: Carol and Dr. Marvin are locked in an underground bunker at "Operation Sky Hook" and the doctor makes a tape recording of himself as the power goes out and the lights start to flicker. He says, "The batteries are failing, the recorder's not running up to speed" but if you look at the tape recorder it never slows down and keeps running at the same speed. (00:25:05)
Continuity mistake: After leaving The Pentagon, Dr. Marvin and Major Huglin arrive at the doctor's hotel in broad daylight. In the next shot as he walks in on Carol sleeping in their room, it's the middle of the night. (00:30:15)
Continuity mistake: At The Pentagon Internal Security Commission meeting a General asks, "Does anyone one want to have the recording played again?" and the two military officers standing in the back move to the left between shots, only to return several shots later. (00:27:45)
Continuity mistake: Dr. Marvin runs out of their hotel room and proceeds to his meeting with the aliens by the Chesapeake Bay. Carol calls Major Huglin in his room and we see that the filmmakers used the same room for both shots with items such as paintings, beds, lamps and water pitchers moved to different spots. (00:33:10)
Continuity mistake: There's no smoke inside of the alien spaceship but if you look closely before the motorcycle cop fires his gun, smoke from a previous take can be seen swirling above their heads. (00:42:30)
Continuity mistake: The alien's show a Navy Destroyer being destroyed by their death rays. Later as it explodes we see the remains of an aircraft carrier. (00:40:40)
Revealing mistake: When Carol, Dr. Marvin and the others enter the alien spaceship it's obvious by the sound that that they are walking on plywood made to look like metal. (00:37:10)
Revealing mistake: As the alien's speak to Carol, Dr. Marvin and the others inside their spaceship, they use the exact same footage again of them looking at the video screen as they leave earth even though one minute of movie time has elapsed. (00:39:25)
Continuity mistake: The alien's speak to Carol, Dr. Marvin and the others and show them a Navy Destroyer on their video screen firing on an alien spaceship. If you look closely the guns on the ship are not aimed at the alien spaceship. (00:40:35)
