It's not only the cabin air that's pressurised. Long before you board a flight, the uncertainties of 21st-century travel crank up the stress levels. Travel documents? Liquids in the right-size bottles? Delays on the way to the airport? Security – how long will the queue be, and how undignified will be the search?
Mix in fear of flying and temporarily unfulfilled nicotine addictions, and it's no wonder passengers are not in the sunniest of moods before they fly off to the Costa del Sol.
Some people reward themselves for successfully jumping the hurdles with a drink or two once "airside", during the indeterminate wait for their plane. But pre-flight alcohol makes the on-board emotional cocktail even more volatile.
Tap "Ryanair flight" into a search engine, and the first response is likely to be a Spanish travel agency, eDreams, which pays for its high position in order to lure passengers away from the official site of Europe's biggest airline.
Type "Ryanair fight" instead, and you find an array of news stories about the latest punch-up aboard a budget flight – FR2306 from Luton to Bratislava on 26 February. After an altercation broke out involving members of a stag party who had reportedly been drinking heavily before the flight, the Ryanair 737 diverted to Berlin where police removed six passengers.
Another passenger filmed the appalling on-board behaviour until he was ordered to stop by a member of the cabin crew. The aggression displayed would be scary enough if you happened to witness it in Luton High Street. But when threats are made and punches are thrown in a crowded and confined cylinder six miles above Germany, it becomes a lot more serious.
After 9/11 and the Germanwings tragedy a year ago – in which a suicidal pilot took control and crashed his plane into a mountain, killing 149 other people – airlines have strict protocols about opening the flight-deck door. But if cabin crew are trying to break up a fight at the back of the aircraft, those procedures may not work. "Unruly passenger incidents are a very real and serious threat to both safety and security," says Iata, the airlines' worldwide organisation.
A typical plane crash involves a chain of events that lead to tragedy – and one link could involve the flight crew's attention distracted because of a drink-fuelled brawl in the cabin.
Flagging the stags
Cabin crew are on the frontline when things kick off, and are obliged to maintain order in the cabin. So they profile passengers as they board. When you think you are being welcomed aboard at the aircraft door, in fact the crew are assessing your propensity for affray – and flagging the stags. While most groups of young males reeking of drink are merely boisterous and good humoured, trouble could be sparked by something as mild as a passenger asking them to tone down their language because children are on board. Once a scrap starts, in a confined cabin it can escalate quickly.
Some cabin crew say privately that they dread being rostered to destinations such as Bratislava, Krakow, Prague and the Baltic capitals. The likelihood of on-board quarrels is, they believe, in inverse proportion to the price of beer in the flight's destination.
The law is an asset
An Irish-registered plane flying from the UK to Slovakia which is forced to divert to Germany might sound a legal muddle. But the law is clear: doing anything that jeopardises the safety of the aircraft and the people on board is illegal.
All airlines warn passengers against disruptive behaviour. Ryanair says: "Customers who create a disturbance at check-in will not be permitted to board the aircraft by our ground staff and if a customer appears to behave in an unacceptable manner or become disruptive during a flight, they will be cautioned by the crew or captain and could be liable for further sanctions upon landing." Those sanctions go beyond a fine for fighting or disobeying crew instructions.
Every diversion triggers costs to the airline running into tens of thousands of pounds. It wouldn't take a super sleuth to track down those responsible and begin civil proceedings to recover the losses. The business affected – in this case Ryanair – knows a lot about the perpetrators, including their names and passport details. The law is an asset in the quest for safety: set an example, and future passengers might think twice about the consequences of their actions
Many airlines warn that they will pursue offenders for damages, but how serious are they?
I asked Ryanair how many aircraft were diverted last year due to unruly passengers; whether the airline tried to reclaim the costs of diversions; and whether those efforts proved successful?
The airline declined to say
I hope you never find yourself aboard a similar flight, but if you do then consider filming events – so long as it does not make matters worse. The more people who catch dangerous behaviour on camera the better. It will help convince the authorities to investigate properly such events, and persuade the airlines to take more care about who they allow on board their planes.