Other mistake: At the start of the film when the commentators are explaining the tie situation between the 3 cars the green arrow to the car is out of alignment and misses the car, instead pointing at the track.
Other mistake: After the first race, in the scene where Lightning is rushing out on the stage thinking he is the winner, loads of confetti is shot out when the King and Chick Hicks gets onto the stage. The confetti is then falling down, but not a single flake hits any of the cars. However, in the following shots, you can see plenty of it on the stage underneath the cars, even though they haven't moved.
Continuity mistake: In the tractor tipping scene, Mater demonstrates to McQueen how to do it using two tractors before Mcqueen's first try. And then when McQueen accelerates to make the noise and we have a wide open shot of the field, we can see that all the tractors in the field are still turning. Missing are the two already done by Mater. (00:55:40 - 00:56:25)
Other mistake: During the very last race, Lightning McQueen gets next to the green car, and the reflection of that green car's chrome "C" emblem is seen on Lightning McQueen's hood. However, the C is facing the right way. Since the C is placed on the green car in the correct direction, the reflection on Lighting McQueen should be a mirror image.
Other mistake: Lightning Mcqueen is trying to become the first rookie in Piston Cup history to win the Piston Cup, but Doc Hudson won the Piston Cup in 1951 the first year that Hudson Hornets were produced, which also would have made him a rookie.
Continuity mistake: Before Lightning falls off the end of Mack's trailer, you can see Snot Rod and one of the other cars running alongside the trailer. But when the camera moves to show Lightning coming off the trailer, you can see alongside the trailer in the background, and the cars are now missing. Camera switches back to the front of Mack, and the cars are back alongside again.
Other mistake: When Mack wants to pull over because he is getting sleepy a car drives by with a mattress on the roof. There is no reason to have a mattress in a world without people, the cars sleep right on the ground/floor.
Continuity mistake: After the first race, McQueen blew out both back tires. When interviewed after the race, his pit crew changes his rims with new tires, but the old rims have tires on them. They should be only rims, since earlier in the race we see him riding "on the rims" only, with sparks flying from the metal touching the track.
Continuity mistake: When McQueen rides on the wall to pass Rusty Cornfuel and Floyd Mulvihill, he passes Winford Bradford Rutherford and Sage VanDerSpin and goes straight to Slider Petrolski. However, past him are Todd Marcus, Ernie Gearson, and Winford Bradford Rutherford again, making it look as if there were two RPM cars with the same exact body, but there aren't.
Continuity mistake: McQueen kicks a can into Doc's slightly-open garage door. The door opens outward. McQueen then slowly pushes both garage doors inward to open them, opposite of how the door was just shown. When Doc subsequently throws McQueen out of the garage he slams the door shut...which would not be possible if it swung in both directions.
Continuity mistake: In the last lap of the first race, the last two cars suddenly change from Kevin Racingtire and Slider Petrolski to Todd Marcus and Claude Scruggs even though the four cars all are nowhere close to each other.
Continuity mistake: Whilst McQueen is in the court room a scratch to his nearside front wheel arch/wing appears and disappears during shots.
Continuity mistake: When the car crash starts, after the camera zooms out, the viewer can see that Eugene Carbureski made it through the wreck, but in the next few frames, it shows Eugene in the wreck.