Couldn't they just shoot at the engines? It's not like they would be shooting at an armored fighter jet. There target would be a big airliner with big engines for targets. Can't imagine one of those reacting to well with a few rounds of lead shot into it. Of course them actually doing that inside a city doesn't sound to smart. One, if they miss those rounds are going somewhere, and two, they actually manage to bring it down instead of the plane hitting some target, more than likely a single building, it now would be crashing down into who know what.