Revealing mistake: In the early part of the chase scene, when the person hanging the banner swings into the pane of glass, you can actually see it start to shatter before he touches it.
Revealing mistake: When the Chinese dragon is knocking over the trash cans you can see they are all perched at an angle on the curb to facilitate being kicked over.
Continuity mistake: At the airport Howard stands in front of a departure sign that says local time is 11:08, yet just a few minutes later Eunice tells Mr. Larabee that it's 12:05.
Revealing mistake: When the sign worker falls off the ladder and swings down to break the pane of glass, his support wire is visible.
Continuity mistake: When Bannister is first shown in the ending scene aboard the TWA plane there is no seat in front of him.
Continuity mistake: Bannister's name tag shifts position onto and off his lapel during the Larabee banquet.
Revealing mistake: During the car chase, the dump truck tailgate is closed when dumping sand onto the Cadillac. With the tailgate open, the sand would not have filled the interior of the convertible.
Continuity mistake: When the reporter leaves the airport terminal with the document bag he gets into a Yellow Cab number 710, with no billboard on the back. When he exits it is still 710, but there is a billboard on the back of the cab.
Continuity mistake: During the chase scene the sun visors on the stolen VolksWagon are visible in some scenes and apparently removed in others.
Visible crew/equipment: There is a boom mic visible when Eunice is arguing with the badge lady over her identity.
Continuity mistake: During the chase scene the sheet of "glass" carried by the workers is too flexible, and is probably a sheet of plastic. The sheet that breaks is not the same sheet that is set down on the sidewalk; the (white) worker's upper suction cup is on the ladder side, but when the sheet is broken it is on the opposite side.
Audio problem: About 10 minutes into the movie, Howard and Eunice are standing at the head of the hotel's escalator listening to Judy define the word "propriety" as she descends; instead of diminishing in volume as it ought to, the volume in this speech stays the same and even increases a little right at the end.
Continuity mistake: When Judy Maxwell approaches the front desk near the start of the movie, signs above where the room keys are kept indicate that the hotel only has 19 floors, with most of the film's action taking place on the 17th. However, when Howard gets in the elevator the next morning (after the visit from Kaltenborn), the elevator starts at floor 31, going up to floor 33 or so before coming out on the unfinished roof restaurant.
Continuity mistake: During the chase scene, Judy and Howard go down a steep hill with large white arrows painted on the road and take a hard left on the delivery bike. On their left side of the hill you can see three cars parked near the bottom of the hill, a white Corvair, a green Pinto and a red Falcon, but when they show individual scenes of the two Cadillacs and the Plymouth taxi that are chasing them down the hill, those three parked cars are gone and now the parking area has a lot more cars parked there then before.
Continuity mistake: When Judy and Howard leave the hotel to go to Larrabee's home, she is wearing the pantsuit she was wearing the night before at the banquet. Just before that, when they are in the roof restaurant, she is wearing a different outfit. But, by that time, the reporter already had her overnight bag, so she could not have changed clothes.