What cost 3,000 lives on 9/11/01 was all of the politicians and citizens who supported the unconstitutional laws enactede over the years, barring private property owners (airlines) from exerting their 2nd amendment right to invite or encourage their customers to bring their "arms" on their aircraft.
There is no way a plastic knife wielding Muslim would have been successful or for that matter even attempeted to hijack an aircraft where there may be 10, 40, 100 armed passengers ready to foil such an attempt.
"They that can give up essential liberty to obtain a little temporary safety, deserve neither liberty or safety." Benjamin Franklin - 1759