My son tends to be scared of loud/intense, but he's seen it twice now and likes it. I went with him the 2nd time and just thought it was sad and dark and depressing. There wasn't enough happy payback for the sad, IMO (and I usually love every Pixar movie). My husband, however, thinks I'm nuts and my kid only seemed to really pay attention to the talking dog and squawking bird.
*spoilers*
He also didn't seem to catch on that when you fall from a blimp or an airplane, you die. I thought pushing a guy out of a blimp and letting him plummet to his death was a little much... but then my son said something about how they pushed him off the blimp and you could tell that in his mind, it wasn't pushing him to his death. And in that same scene, 3 dogs obviously die in plane crashes and he didn't seem to get that either - he just keyed in on the joke part leading up to that. So I'd definitely say the dark undercurrents are lost on the littler ones. Thankfully. And like someone else said - it is rated PG.
