In Pixar's Cars, Lightning McQueen's primary sponsor is Rust-eze.
Rust-eze is a fictional medicated bumper-ointment company whose branding covers Lightning's red racing body during his rookie season. The sponsor is represented by Rusty and Dusty Rust-eze, two older Dodge vans who support him financially and promote their product.
Lightning initially dislikes the Rust-eze association because he wants the prestigious Dinoco sponsorship. His attitude changes after his experiences in Radiator Springs, and he ultimately chooses to remain with Rust-eze rather than abandon the company for a more glamorous deal.
The sponsorship is an important part of Lightning's character arc. It shows his movement from status-seeking ambition toward gratitude and loyalty. Rust-eze branding remains visible in later Cars films, even after Lightning becomes a major racing star.