Personally I do on occasion require a G&T on a plane just to calm my nerves as I can be a nervous flyer at times. I have no intention of drinking excessively, I would just have 1 in the airport before boarding and maybe another 1 during flight if required. I appreciate that smokers need cigarettes to calm their nerves, but unfortunately to offer the ability to smoke without disturbing any other customers is a lot more difficult than to offer the ability to have a calming drink. I would be more than happy to pay for a G&T on the flight if that would stop people from getting drunk on the plane, I don't particularly see any reason why alcohol should be provided for free in economy class if it's going to lead to problems with drunks.