Trivia: Doc Hudson's character is based on a real racing team from the early fifties, with a car named the "Fabulous Hudson Hornet". Also, the reason he told McQueen he was "out of date" and not wanted after "recovering" from his accident is the same reason the real Hudson Hornet ended its dominance of Nascar around 1955: the introduction by Chevrolet of the OHV small-block V8 engine. There are history pics on the web showing cars with the same paint job Doc Hudsons had as he was shown being the pit crew boss in the final race.
Trivia: The two Masserattis that are with Michael Schumacher Ferrari in the end of the movie actually appears earlier in the beginning of the final race; they are entering the security area with Fred when he cannot get in even when Mario Andretti says his name. We can see the license plate of the green Masseratti in the epilogue when the wheel well is being reopened. The license plate is B9513.
Trivia: The train which almost crashed into McQueen when he was on his way to Radiator Springs has the number A113 on it. Mater's license plate is also A113. This is a recurring inside joke in several animated shows and films, referring to the number of the classroom used by animation students at CalArts.