I always keep my laptop handly to lauch.
I wear wood-soled clogs when I fly because I think they'd make a good club. And I always carry a metal pen with me, in case I have to stick it in a terrorists eye or something.
LQ
A more effective approach is to take your belt, come up to the perp from behind, quickly put it over his head/around the neck and quickly turn and pull him up on your back. By turning you twist the belt around his neck and cut off the blood flow to the brain. Count to 4 and he will be passed out, count to 5 and he will be dead. I learned this in Marine Corps recruit training 35 years ago and they actually demonstrated this using me as the chokee. It does work.