FN FAL said:It's already happened or been attempted. A large freight company had an attempted hijacker on a suicide mission and a PSA BAC-146 on the west coast was crashed after an airline employee got a gun on board the aircraft, shooting his supervisor and the two pilots.
Also, they believe Egypt Air was doomed by a pilot. It's nothing new.
I have to disagree.It is something new.Neither of those accidents had a terrorist crewmember simply drive one into a building after simply taking out the Captain or FO next to him.