He takes a puppy with him in a small, open cockpit into a firefight and he doesn't think anything bad will happen? He's lucky the dog didn't jump out of the plane trying to get away from the loud noises the first time they went up.

I'm not sure I understand the train of thought behind "the people I fight with and now my dog have died pointless deaths; this killing is tragic, so in response I'm going to kill as many people as I can."

Then again, maybe that's the whole point. He's been so degraded by war that even when he tries to be human, he can't quite do it.