Was at BRS the other day and got a pint of Butcome at the airport bar. On the flight to GVA a 33ml crap lager cost more (and they paid zero VAT/Duty). Bar-stewards.
There were plenty of times that I flew UK/Switzerland/UK and I never paid for a beer once ... with Swiss, I was tempted to quote "you get what you pay for" but often Swiss were cheaper than LCC's!
But credit where credit is due ... SAS, the only airline I've flown with that served low alcohol beer, I had my car to drive after landing and SAS served the perfect alcoholic beverage under the circumstances.