B747-337M, come on, tell that to El Al, who has had bullet-proof cockpit doors on thier whole fleet for a very long time. And who is to say a highjacker won't bring a gun on board (and don't tell me airport secuirty will notice it, because they may not)? Plus, bullet proof doors also keep hijackers out of the cockpit. Unlike the week, standard doors right now, they can't be opened by force ("stabbing" the door, ramming into it, etc., etc.).