I really think that when boarding, the ground staff should check every passenger for signs of being drunk. These travellers are a threat to security and make the 200/500 travellers voyage a nightmare. My flights have been completely spoiled 3 times, a drunk laying in the aisle , a young man vomiting all over the place, and the cherry on the cake, a completely drunk man allowed to board a Lufthansa flight , created havoc, smoked, threw things around, and finally his meal tray all over my direct neighbour ! All this despite me signalling the stewards before takeoff that he was in a bad way. My neighbour and I refused to stay in our seats and were finally moved behind the cockpit where the pilots rest seats are. The man was handcuffed to his seat and arrested on arrival. My seat neighbour and myself got to see the landing, which was great, but what a way to start a holiday.