A few notes on style.
1) In closed circumstances like that, it is generally much better to use hammer fists than knuckle punches. Heel palms to facial areas. Sharp elbow smashes to the rib cage are just peachy. Broken collar bones are a must, and only take 15 lbs of force. Broken collar bones = no arms.
2) Don’t stop until it is very, very obvious that your efforts are no longer necessary. A violent and threatening individual should have a minimum of six months hospital recuperation before imprisonment is even an option.
3) Don’t ever assume they are working alone. Keep an eye out for confederates. Since you are not a LEO, racial profiling is a must, and often works. If “plan ‘b’” does anything suspicious at all, be on him “like a duck on a June bug”. This doesn’t mean attack him, but real sure that if he pulls something he will quickly be examining the carpet. FYI, these mugs often travel in groups of 4-6, so it could turn into a real brawl.
And “More than 1 means ‘life or death’.”
Some observations about this deal...the guy was in the toilet for 30 minutes? I’m guessing he was enjoying some of his drugs or the drugs he had digested were messing him up. He wasn’t on the passenger list? The only way to make that happen would be to have a airline representative arrange your entry without really taking the “pass” (which I’ve stood over the past five years and seen this done twice).
A heavy object to the back of the head can stop a struggle.
Certain ballpoint pens have nice strong metal tips -- sticking one up against his eyeball will stop his desire to struggle real fast. Alternately, a sharp ballpoint pen jammed forcefully into the throat or into a kidney will end things permanently (only if there's a general melee and there's more than one bad guy, indicating a life-or-death situation).
A belt with a good buckle makes a decent weapon for flailing or as a garotte.
Etc.
Think ahead of time what you could and would use as a weapon against a terrorist attempt.