Most machine gun bursts didn't hit their targets - but they had to land somewhere. I've read a lot of WW2 history but never heard stories about where those bullets ended up. Are there any known incidents? Were many stray bullets erroneously put down to the enemy deliberately strafing civilians (which did happen deliberately as well, from both sides)?
Not an aerial battle per se but the hysteria of the "Battle of Los Angeles" in 1942 over 1400 AA rounds were fired into the skies over Los Angeles. Some buildings were damaged and 5 people died (though not from the artillery fire itself, from car wrecks attributed to the chaos I think).
It is not unfathomable that unexploded ordinance killed someone falling from the sky over the course of the war. I'll keep looking to see if I can turn up something concrete.
This was covered about 8 months ago: http://www.reddit.com/r/AskHistorians/comments/1e85yv/during_the_air_battles_over_western_europe_in/
Basically, yes. This was a relatively common thing. At the time, I pointed out how badly Hawaii was tore up by its own AA fire during Pearl Harbor.