In Pixar's Cars, the number painted on Lightning McQueen's race car is 95.
The number appears prominently on Lightning's red body and is used throughout the Cars franchise to identify him in races, merchandise, and promotional material. It is a visual signature as important to the character as his lightning-bolt decals and Rust-eze branding.
The number is commonly associated with 1995, the year Pixar released Toy Story, its first feature film. Pixar has used references to 1995 in other contexts, making the connection especially recognizable to fans, although the films do not present the number as a racing statistic or championship count.
Number 51 belongs to Doc Hudson's racing history, while 43 is strongly associated with real NASCAR champion Richard Petty. Those familiar numbers can make plausible alternatives, but neither identifies Lightning McQueen.