Yet that doesn't stop people getting on board drunk or ploughing through the alcohol during the flight.
Businesspeople are notorious culprits, particularly after conferences and exhibitions or whenever they travel in groups.
The reason travelling by air drunk is illegal is primarily to do with safety. In the event of an emergency, if an aircraft has to be evacuated, people with impaired reactions as a result of too much alcohol can be an obstacle to those wanting to escape as quickly as possible.
Stories are legion about the disruptive factor of drunk passengers causing disturbances during flights or starting fights. Or even causing planes to divert to alternative destinations in order to eject rowdy passengers.
Problems with drunk travellers don't stop once they've left the aircraft, however. Many go on to rent cars and drive them while intoxicated.
The problem has become so severe that airlines are now seriously weighing up the commercial benefits of selling alcohol on board with the consequences, as a result of inebriated passengers.
Excessive intake of alcohol on long-haul flights has serious health implications, particularly for people with circulatory or blood-pressure problems. Health experts say it's a better idea to stay hydrated and drink lots of water when you fly, particularly if you're straight out of the starting blocks and have to work when you land.