Revealing mistake: In several shots when Babs is in the showers, the girl in the shower next to hers can be seen to be wearing a blue swimsuit. (01:15:10)
Other mistake: In the scene when the helicopters arrive over the research center, look at the heli in the bottom right - it just fades out, while one on the left materialises, and the one in the middle changes position. Notice that after all the helicopters have changed place, you can see the helicopter that faded out appear on the helipad. (02:25:25)
Continuity mistake: The hot dog vendor opens the sausage compartment. The shot changes, and it's closed, and he opens it again.
Continuity mistake: When Carl lets his dog out of the bag, in the close-up there's a shadow on Rod Steiger's boot, and a shadow of something or someone standing between him and the camera: both are gone in the following shot, when the dog runs across the lawn (and 'knocks aside' the camera). (00:08:20)
Visible crew/equipment: When Neil and Brenda are in the row boat, the bulge of the mic transmitter is visible at Brenda's lower back. (00:43:45)
Continuity mistake: When the Senior Civil Servant is reading Dowding's letter there is a knock at his door. In the next frame the Civil Servant has removed his glasses, appears more leaned back in his chair, and the position of the letter/page has also changed. (00:06:00)
Factual error: Someone forgot to cover the air conditioners in the opening number of "Hello, Dolly!" which is set before the turn of the 20th century. (00:02:59)