Revealing mistake: When the train is sliding along the ground near the end, there are sparks coming from the underneath (supposedly where the metal scrapes the pavement). Look more closely, and you can see that the sparks are coming from a bit of the train that's not touching the pavement anywhere. (01:44:55)
Revealing mistake: At the end, when the empty bus rams the freight plane, the wire pulling the bus can be seen. Most obviously in the low shot shortly before impact, where there are several wires/shadows on the ground leading towards a fixed point in the runway beyond the plane.
Revealing mistake: In the scene where Payne is waiting for the money to be dropped into the bin, he looks through the blinds out onto the street. When he lifts up the blind with his 'bad' hand, you can see his fingers and thumb taped up out of the way.
Revealing mistake: In the scene where Jack and Annie escape from beneath the bus via a trap door, the shot of them skidding across the runway shows a ring on Jack's left hand as it is wrapped around Annie. Jack is not married in the movie, but his stunt double must be.
Revealing mistake: As the bus makes the impossible right turn at high speed, you can see the outrigger wheels underneath to stop the bus going over.
Revealing mistake: In the scene in the subway Denis Hopper has again used an explosive jacket like that used at the start of the film, which is detonated if the remote trigger is released. However when on the subway train, Denis takes the remote back from Sandra Bullock and it is seen that the trigger is quite obviously released and Denis pushes it back in.
Revealing mistake: When Traven is walking back to his car before the first bus explodes, as the bus drives past him, you can see from the shadow it casts that the bus isn't driving straight on. It turns the corner behind his car. Obviously a prop bus is further down the street and that is the one that blows up in its place.
Revealing mistake: When Howard Payne's house explodes, a wire is visible as it pulls back one of the police officers who gets "blown back" by the explosion.
Revealing mistake: After Jack has taken command of "Tuneman"s car, in the wide shots of them chasing the bus you can tell it's not Keanu Reeves driving. The stunt driver has slightly longer hair in a more squared crew cut.
Revealing mistake: When Jack is fighting Dennis Hopper on the roof of the subway train, a piece of paper falls off one of them and then stays surprisingly still considering they're on a speeding subway train.
Revealing mistake: Before Jack rips the door off the Jaguar, he speeds ahead of the bus and then opens the driver's door at highway speed. At 50 MPH there would be a lot of air resistance, yet Jack opens the door effortlessly.
Revealing mistake: The Boeing 707 freighter that gets blown up by the bus bomb is obviously a "scrapped" plane (a plane that has lived out its usefulness and is being readied to be scrapped). One good way of telling this is the plane's exterior shows heavy weathering wear from being stored a long time. But someone told me the way it looks could also be a hasty paint job using ordinary house paint. Either way, it's still something to look for.
Revealing mistake: At the beginning, when they're talking about "shoot the hostage," the angle of Keanu Reeves is out of focus for a good five seconds. It drifts into focus.
Revealing mistake: The monitor Payne is using to the watch the inside of the bus is nowhere to be seen every time the inside of his hideout is shown. Only until it's revealed he had a camera hidden is the monitor shown.
Revealing mistake: When the bus jumps the gap and comes into land, you can see there are no passengers, not even dummies.
Revealing mistake: In the elevator, Payne grabs Detective Temple by his nose holes, but it's very obvious that Payne is not grabbing his nose and Temple is pushing himself sideways and upwards with his left arm.
Revealing mistake: When Howard shoots the subway driver near the end, we see the driver collapse and die. Where did the damage from the bullets go? There's not much in the way of bullet holes or broken glass. Certainly an automatic weapon would've produced some damage.
Revealing mistake: When Jack is under the bus attempting to dismantle the bomb, if you look closely, when the cable comes off the hook, you get a shot of Norwood and the Lieutenant standing on the edge of the van holding the cable - you can see that it's their stunt doubles standing there.
Revealing mistake: In the elevator scene, when Jack looks up standing on top of the elevator, you can obviously tell that he is in front of a rear projection. Notice the elevator ropes don't move one bit.
Answer: He's taller now because he has his head while the villain does not!
Grumpy Scot