Yeah, it's certainly a big success to use the plane as a bomb. I'm really just trying to say, and obviously doing a bad job at it, that i don't think access to the cockpit is required to achieve this. So far that hasn't been demonstrated, but the fact that the cockpits were so accessible in the past obviously meant that people didn't need to worry about it. I predict in the future we'll see similar attacks carried out, despite not getting access to the cockpit. It'll require creativity, but it just seems like a matter of time to me.
If you want to just kill a lot of people there are far cheaper and more effective ways. Check out the concerts being attacked.
So the door is all you need.