Mater, Finn, and Holley are tied down on Big Bentley's gears, ready to be crushed when the gears run into each other. It is established that the gears rotate for every minute that passes on the clock. When the clock reaches the time of 3:02 they are all two minutes away from being crushed. The scene cuts away and when it returns, the clock face clearly shows a time of 3:05, but the gears have not moved inside.
When Axlerod is arrested, the police car to the left is gray, while the police car to the right is black. After Mater opens Axlerod's hood, the black police car is silver.
When the cars are lined up for the first race, the action by the cars behind Lightning McQueen does not match between the racetrack and the video screen above the race.
As Lightning & Mater are heading back into town after Mater's day of fun, Mater is on the left and Lighning on the right. Lightning drives in front of Mater to tell him he's having a quiet dinner date with Sally and when we cut back to Mater he's now on the right of the road.
When Mater, Finn and Holley are in the jet, the lines on the carpet between Finn and Holley change between shots (before the hologram is seen).
When the cars race from Trafalgar Square to the Mall, they go through Admiralty Arch. All three main arches are open. In reality the central arch is always closed to traffic except on state occasions when the Royal vehicles are allowed through that way. Normal traffic only uses the outer two main arches.
Mater is having trouble entering the roundabout at the Arc de Triomphe. Incoming traffic has the right of way at this roundabout.
When the race tracks are shown for the Japanese, Italian and British races, the Union Jack is shown with all the white lines being the same width. In fact the red diagonal cross is offset, so that on each diagonal, the white lines each side of the red are different widths.
Francesco Bernoulli is Formula One, not a stock car; he would not race in an "official" competition with McQueen.
Siddeley, Finn McMissile and Holly Shiftwell's private spy jet, is a Gulfstream V. He takes off and lands vertically, even though Gulfstream V's are not VTOL aircraft.
When Tow Mater is knighted, he would not be referred to as "Sir" either by the Queen or on the billboard. Only citizens of countries recognizing the British Monarch as their head of state (e.g. UK, Canada and Australia) may use this title. Citizens of other nations may never be called "Sir" when receiving an honorary knighthood. This is why Mater doesn't want the Queen to call him "Sir" after being knighted.
Brent Mustangburger has clearly visible white walls on both the inside and outside of his tires. Tires are manufactured with a white wall on only one side of the tire so that the user can decide whether or not to have them visible when installed on the vehicle.
When the starting lights begin to count down before the first race begins, Lightning is wearing his tires from the party, and not his lightyears.
In the Japanese dub when Finn is telling Holly that he will go after Zundapp and she should help Mater you can see Finn's mouth move without any dialogue just before the line. This issue is not present or greatly minimized in all other language versions of the movie.
Lightning McQueen calls Sir Miles Axlerod "Sir Axlerod" several times. The correct way to address him would be "Sir Miles"; a knight is addressed as "Sir" followed by his first name.
In the talk-show scene before Sir Miles Axlerod comes on screen, a car which appears to be Lightning McQueen very briefly appears on the WGP graphics. The incorrect car is used, as the "trails" seem to correspond to the car's country, and the trails with Spanish flag colors (red and yellow) have what seems to be Lightning McQueen on them.
J. Curby Gremlin introduces himself as "from Detroit". Gremlins were made in Kenosha, Wisconsin.
When Holley Shiftwell is about to fix Mater's dents, she presses the button to withdraw the sander before she is told that Mater doesn't them fixed.