[ars_technician]

Do you not think someone would spot them sawing the door open? Also keep in mind that pilots are FLYING THE AIRPLANE. They can just start to do maneuvers that would make it impossible for attackers to even stay at the cockpit door, let alone take it apart.

[warmwaffles]

Pilots would ground the plane before doing ludicrous maneuvers like you are suggesting. Those planes aren't very nimble.

[jrockway]

Completely false :)

http://en.wikipedia.org/wiki/FedEx_Flight_705

"About twenty minutes after takeoff, as the flight crew carried on a casual conversation, Calloway entered the flight deck and commenced his attack. Every member of the crew took multiple hammer blows which fractured [the flight crew's] skulls. A lengthy struggle ensued with the flight engineer and captain as Tucker, also an ex-Navy pilot, performed extreme aerial maneuvers with the aircraft, at times flying upside down, with the intent to keep the hijacker off-balance."

It worked, too. Everyone survived.