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)
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)
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)