Lawdog you are giving the terrorists far more credit than they deserve. They are not Green Berets, nor are they Chuck Norris. Call me over-confident, but I'm quite sure I could have taken out any of the 9/11 terrorists with what they were armed with. The reason they were successful on 9/11 was surprise. No one thought of suicide terrorists in the US at that time. Now we know and now we won't hesitate to react. If the terrorist manages to bring a semi-auto on board then yes the first few who fight back may get torn up. Otherwise I'm sure we can overwhelm anyone who brings a knife to a gang-bang.

As for the cockpit door being open, yes it is at times. In fact in Europe on many flights today they still leave the cockpit door open throughout the flight. But while the pilots fight back, us passengers and the FA will have time to get up there and assist.