I don't drink at all when travelling - mainly due to my pathological hatred of toilets on board planes - but my late husband could quaff my share as well as his.
Usually this wasn't a problem although some US cabin crew would tut loudly if he asked for another bottle of wine with his dinner and a brandy to put in his coffee afterwards.
I did travel with him once where he unfortunately got so drunk in a pub before we even made the airport that by the time he got there he was rather belligerent to security staff at LTN and ended up getting offloaded, which mortified me.
It's probably just as well he never did get status on BA (he generally flew EZY) because he'd have been like a kiddie in a sweet shop in the lounge