I set up an account on the site just so I could reply to this review. The question of "where do cars and planes come from in-universe" is kind of... ambiguous, and deliberately left that way, I think, though Cars 2 hinted at manufacture in some cases. Nevertheless, the first Planes movie further muddied those already murky waters by making several explicit references to "birth". I think it is a case of "choose the version of the story you'd rather go with", because seriously, the idea of PEOPLE (that's what they are, in the in-universe context) being put together from parts in a factory is a major creepout and a really discombobulating "fridge horror" thought. Disney/Pixar would be wise to keep that "in the mists" as it were.
Another issue that messes up the "from factories" theory is "so where did the wildlife come from?" Where did the "Deeres" and "airplane birds" originate, if not naturally? Would factories be natural processes or something involving a divine act of creation? "The Manufacturer" is referred to in an almost godly context which might suggest that is valid. Perhaps they "reproduce" more than one way, by the "bio" method or from factory matrices or a combination of the processes. Are you thoroughly confused yet? Well, you DID post a review that was refreshingly and entertainingly different from the usual relflexive bashing that the Cars/Planes franchise movies get from other critics, which says you actually THOUGHT through the implications of that universe, so thanks enough for that.
Funny how people can take talking toys and talking animals and talking snowmen and people breaking out into song every so often, but talking vehicles kick their butts.