I think the drill, bow and 7+" long tools are so you don't put a hole in the air frame. It's not that thick. Although it's doubtful you'd have an explosive decompression, I suppose there is a risk. But I think the entire plane would freak out if you put your battery operated 24V Hammer Drill armed with a 10" long diamond tipped titanium bit against the fuselage and pulled the trigger. An arrow could puncture it probably as well as a bullet - I've never tried to get on a plane with bowhunting gear... anyone get on with carryon bow and a quiver full?

I wonder if my sai would be considered a weapon or a tool or both? :-)