Cars introduced Lightning McQueen and Mater as Pixar feature-film characters.
Released in 2006, the film begins with McQueen as an ambitious race car and introduces Mater as Radiator Springs’ friendly tow truck. Their unlikely friendship develops after McQueen is stranded in the town and must repair the damage he caused.
Cars 2 later moves the pair into an international spy adventure, while Cars 3 returns to McQueen’s struggle against a new generation of racers. The characters also appear in Pixar shorts and television productions connected to the franchise.
Planes is a separate animated film from Disneytoon Studios, set in the same broad fictional world but not produced as a Pixar feature. It is therefore not the film that originally introduced McQueen and Mater.