The DVD version of the movie makes it easier to spot a few amusing Pixar self-references: The Pizza Planet Truck (from Toy Story ) and the iconic Luxo Jr ball can be seen on the streets as Carl's house breaks free and floats away. Then, Carl and Ellie's plane tickets show flight 2319 (the kid contamination alert number from Monsters, Inc ), and later in the film, Carl is served the same scallop dinner featured in Ratatouille.