As the number of unruly, disruptive or downright violent passengers continues to rise, a number of airlines are trying to do something about it.

In Europe, Ryanair has taken the unprecedented step of banning all duty-free alcohol purchases at the airport by passengers before their flights from UK airports.

From now on, any duty-free booze must be checked in, and any passenger attempting to smuggle alcohol into the cabin could be removed from the flight.

Earlier this year, 15 drunken passengers were kicked off a Ryanair flight, causing a five hour delay.