Conglomerate Blog: Business, Law, Economics & Society: "That being said, the Cars/Planes story lines don't overlap. Lightning McQueen and Mater are not here. But, some very minor characters reappear (Brent Mustangberger, e.g.), and the "extras" are the same. The Planes world is the same as Cars world; it is a post-human world in which motor vehicles populate the earth. (have you seen this intriguing yet forced explanation of how all the Pixar movies fit together into a timeline between Brave and the post-human world of Cars?)"
'via Blog this'