Continuity mistake: Before the race in Thomasville Cruz has the 20 number only on her right side but later she has the number also on her left.
Revealing mistake: When Lightning, Cal and Bobby enter the pit row, the King's model is merged with the one from the crew chief next to him. (00:03:05)
Continuity mistake: When McQueen almost hits Smokey he stops few inches away from him, but in the next shot that distance increases notably.
Suggested correction: It's set in McQueen's perspective.
It's not in McQueen's perspective. We see both cars from a different angle, and they are further apart than the initial stopping point.
Revealing mistake: When Lightning McQueen is being shown the simulator in the plant, the times shown on the simulator don't work. A regular timer would say, for example, 21.99 seconds, but the timer on the simulator screen only goes up to 21.27 seconds, if you watch it. I assume this is because of the Frame Per Second of the movie, and wasn't noticed, being as most cartoons etc run at 25-30 FPS.
Factual error: In the end credits, some of the vintage advertisements have 770 area code phone numbers, which while valid for Atlanta, Georgia and surrounding areas now, it didn't exist until 1995 when it was assigned. The numbers should have had either a 404 or 912 area code since those 2 area codes covered all of Georgia until 1992 when area code 706 was implemented.
Continuity mistake: Near the beginning of the movie, as Lightning McQueen prepares for the race, Mater tells everyone to be quiet for Lightning McQueen. We get a shot of Lightning McQueen from inside Mack's trailer, outside the window there is a wall and there's nothing on it, but as the camera switches angles from Doc Hudson back to McQueen, there is graffiti on that wall.
Continuity mistake: During the Los Angeles 500, the Next-gen Carbon Cyber racer Chris Roamin' can be seen behind McQueen. However, when McQueen crashes, Roamin' is nowhere to be seen and instead the Next-gen Nitroade racer Tim Treadless and Next-gen Easy Idle racer Harvey Rodcap are behind McQueen.