Cheaper airline tickets and boozing passengers have been blamed for an increase in the number of abusive incidents occurring on flights, a trend that one international air organisation has described as being a major problem.
The International Air Transport Association (IATA) said its members reported an average of 150 incidents of disruptive passenger behaviour each week on flights around the world last year, and there was a "clear, general upward trend in instances of unruly and disruptive behaviour on board aircraft in commercial airline service".
In the past month, a number of planes have been diverted after passengers got into fights. Some were over reclining seats. In one, an Australian man was charged after allegedly repeatedly punching a sleeping passenger in the face on a flight from the Philippines to Sydney. In another, a Cuba-bound flight was given a military escort back to Canada after two women allegedly drank their duty-free alcohol in the plane's toilet, set off the fire alarm with a cigarette and got into a fist fight.
The incidents are not only disruptive and potentially harmful for passengers and airline crew, but can cost the airlines hundreds of thousands of dollars if the plane is diverted.
One Australian aviation source said it was a common view within the industry that the relative cheapness of flights had contributed to an increase in abusive behaviour on planes.
"Thirty years ago it was expensive and therefore a better type of person travelled," the source, who asked not to be identified, said.
"People were on their best behaviour and dressed up in their Sunday best. It was a special thing to do. Now you just go in your board shorts and thongs, pay your 50 bucks and jump on board."
The Australian Federal Police said 67 people - or 5.5 people on average a month - were charged with offences relating to offensive and disorderly behaviour on board an aircraft or at one of the 10 Australian airport precincts it policed in the 2013-14 financial year.
That was up from the 50 incidents recorded in the 2012/13 financial year, and 64 the financial year before.
"Instances of antisocial behaviour often involve alcohol so passengers should consider what effect their alcohol consumption has on fellow passengers and crew, and drink responsibly," an AFP spokesperson said.
"The cabin crew should not have to be abused, threatened, or interfered with while conducting their duties.
"This same standard also applies to fellow passengers, who did not deserve the inconvenience of their trips being cancelled or delayed."
IATA, a trade association representing 240 major airlines across the world, including Qantas and Virgin Australia, said unruly passengers were a small minority of the flying public, but unacceptable behaviour on board an aircraft could have serious consequences.
Between 2010 and 2013, IATA's members reported 20,000 unruly passenger incidents, including 8000 in 2013 alone.
In-air offences ranged from "physical assault" to "failing to follow lawful crew instructions," as well as "consumption of illegal narcotics, sexual harassment, and physical or verbal confrontation or threats", IATA said.
"Intoxication, often resulting from alcohol already consumed before boarding, ranks high among factors linked to these incidents," Tony Tyler, IATA's director general and chief executive officer, said.
"Other causes included irritation with another passenger's behaviour, frustration with rules such as smoking prohibitions or use of electronic devices, or emotional triggers originating prior to flight."
IATA says policy changes are needed to the outdated Tokyo Convention, which was drawn up in 1963 and governs how cabin crew and pilots respond to unruly behaviour. That convention assigns jurisdiction for any offences committed on a plane to the country the aircraft is registered in, not necessarily the country the plane is landing in, IATA said.
Proposed policy changes, formally known as the Montreal Protocol 2014, were announced at the International Air Transport Association's General Meeting in Doha, Qatar in June.
"By extending the jurisdiction from the country of aircraft registration to the destination country, the protocol closes a loophole that allowed many serious offences to escape legal action," IATA said.