Yeah...it's just the timing involved. What if the plane was late or something? A lot of the action in this movie came down to split second timing: The Tumbler boosting in front of the armored car to intercept the missile, Joker mentioning the school bus, it backs into the bank a moment later, and then joins the line of other buses. Joker's getaway from the hospital, on and on.
Still a great movie, everything I mentioned in this thread was just too much.