Revealing mistake: Near the end when Ace gets into his Cadillac, in the first shot facing the front of the car, there is a protective glass in front of Ace (the same width as the windshield) with the dashboard in between that glass and the windshield. Note the vertical edge of the glass is visible at the right side, and the rearview mirror's sticker on the windshield casts a shadow onto the second glass. During the stunt, the flames on the dashboard are between the glass shield and the windshield, keeping the actor safe from harm. (02:46:05)
Continuity mistake: Right before they rob the police car, a Boeing 747 (four engines) is seen in shots of the plane coming into land. When the plane is shown from behind, it is a Boeing 767, with only two engines and fewer main landing gears. (00:30:10)
Revealing mistake: When the computer is being hacked and the password and/or code for the database is shown on the screen, most of the display is for an Autodesk printer driver. (01:39:00)
Other mistake: When Somerset goes back to the man's house alone, he cuts a sticker on the door with his switch-blade to get in. The first error is the sticker is on the inside and it says "Keep Out." The best part about it is the door opens inward. How did they put the sticker on the inside and then exit? (00:20:45)
Continuity mistake: Towards the end, when Bruce Willis notices the writing on the aspirin bottle, he leaves it in the phone booth and the camera jumps towards it a couple of times. In the first shot the writing's almost vertical, but in the following shots it's at a definite angle. (01:48:35)
Visible crew/equipment: In the drive-in shootout scene, the camera and crew are visible in the rear view mirror in the cab of the white Dodge pickup fleeing De Niro and Kilmer.
Continuity mistake: When Sandra Bullock is looking on the screen at an IP address, we cut from her and the monitor to just the monitor and the IP address changes.
Continuity mistake: When Wallace is put into his overalls he's still wearing his green pullover. A moment later he suddenly doesn't wear it anymore but a complete white shirt. He couldn't have just taken off the pullover as the shirt under it is actually fake (The collar is actually part of the pullover and the arms are just stuck on).
Continuity mistake: Two-Face and the Riddler are in Two-Face's lair; the Riddler has just said, "Then I taught my doggie a new trick; how to map the human mind." In the establishing shot, the tube is in left hand; after the cut, it's in his right hand.
Visible crew/equipment: When Salma Hayek is tossing the bullet she has just removed from Antonio Bandaras's shoulder, you can see the reflection of Robert Rodriguez holding the film camera on the metal dish.
Continuity mistake: Miguel Bain escapes from a police car by snapping the neck of the cop who was driving. The wide shot shows however that the cop is still very much alive and driving. (00:15:32)
Continuity mistake: When the guards fire at John and Charlie and the mugger, 3 tiles on the pillar get shot clean off. When John and Charlie are emerging from behind the pillar, 2 of the tiles have bits back on the pillar. (00:07:15)
Visible crew/equipment: Whilst the group of Southeast Asian men are walking through the hair salon, there is a shot that starts with a male hairdresser wafting a blanket, that pans over to the group of men and then the camera rotates around the man holding a little girl. Immediately after the camera passes the man and girl, the camera very briefly holds on another man waving to an employee. Just as this happens, the reflection of the cameraman can be seen in the mirror to the left of the shot. (00:31:30)
Suggested correction: It's for effect to show they were hanging out around the airport for more than a bit.
There's no evidence this was meant to be a montage scene of various planes. The cuts they did have in the first angle were of the same plane getting closer to build suspense. Same for the other angle. Plus, there's no scenes or shots of "them" waiting.