Pizza Planet delivers!
If you can’t get enough of that Pizza Planet truck, Wikia has a box full of images on the cameo appearances this delivery vehicle has made in various Pixar projects. License plate number RES1536 and seen in both Toy Story films, there is a bumper sticker on the rear bumper that reads “How’s my driving? Ha ha ha ha ha!”.
They’ve found the truck in almost all Pixar feature films with the exception of The Incredibles (I’ll bet it’s there, somewhere).
Pizza Planet truck - Pixar Wiki
Update: There’s been some debate over at Wikia as to whether a couple of frames in The Incredibles shows the Pizza Planet truck seen on the road while the family is driving to fight the Omnidroid. The colors are right. What do you think?
