Some time back I was strapped next to a drunk on a flight from Houston to London, fairly drunk (staggering) when he boarded, completely unconscious and incontinent on arrival ~11 hours later. The change was thanks to his being served beers 2 at a time the whole way.
I remember the cabin crew member taking his pulse when she couldn't rouse him to put his seat belt on - she never really did get it fastened securely.
"We can well understand the annoyance and inconvenience caused to you. While it may have seemed that firmer action by our cabin staff could have alleviated the problem, there is always the danger of creating greater unpleasantness if request for drinks are refused. Intervention can sometimes inflame the situation."
BA Customer Relations, 3/4/1998. Have only flown with them when there was absolutely no other alternative since that day.
So please don't complain if passengers are drunk on your aeroplanes, emember that getting them as drunk as possible is a policy adopted by airlines to avoid greater unpleasantness.
Back to lurking now - I've learnt a lot of interesting things here.