In a comment at the post below readers discuss having had nail clippers taken away from them at airport screening points so they could not be used as weapons on the flight.
Yet as others have pointed out, there is an axe on board the airplane for emergency use, and even a Bic ballpoint pen or plastic cutlery could probably be used as a deadly weapon if someone was able to file a sharp point on it.
But the discussion made me think of a story from long ago...
Over drinks one evening a female friend told a group of us at a party about the time she was home alone and heard a noise at the back of her house. The fact that her Irish Setter alerted to the noise raised her heart-rate and blood pressure. She walked toward the back door of the house, dog leading the way, and passed through her utility room where she armed herself with the closest weapon she could find... a twirler's baton.
(She taught baton-twirling professionally).
At which point I asked, "What did you intend to do... TWIRL HIM TO DEATH?!!"
I'm betting a twirler's baton is another item that would not be allowed in hand-carried luggage!