If you've ever wondered why you lose our ability to tolerate others the minute you cross the air bridge from the gate lounge to the aircraft, there is one good reason for it: the diminishing lack of personal space per passenger.
With seat pitch (that is, leg room) now running an average of 32 inches (81 centimetres – and a six-foot (183-centimetre) man's legs running an average 36 inches (91 centimetres) – there is no greater impetus for loss of humanity than the guy in front putting his seat back, suddenly, violently into your little patch of economy class hell.
We've all been guilty of it – the minute the seatbelt sign is extinguished after takeoff, we hit the recline button in a bid to claim as much of that personal space as we can. Hey, it's not like the person behind you can't do it. At 30,000 feet, with 17.5 inches of seat width and no room to bend down and tie a shoelace, it's every man and woman for themselves.
But if the person behind you wants to work on their laptop, or reach the bag they've dutifully stowed under the seat in front (that is, your seat), or get up to go to the loo, or maybe even enjoy their inflight meal, your fully reclined luxuriating is going to be about as welcome and tolerable as a six-hour delay.
Things reached boiling point this week during an inflight donnybrook on United Flight 1462, which forced an unscheduled landing in Chicago en route to Denver from Newark when one passenger installed a "Knee Defender" device that stopped the passenger in front of him from reclining.
These rules are indisputable: You do not recline your seat if it is a less-than-three-hour flight. Particularly on the busiest route in the air, Sydney-Melbourne, just don't.
As attractive as the Knee Defender sounds, before you go shopping online for one, make sure you don't use it on Virgin Australia or Qantas.
"The use of knee defenders or similar device would be in breach of our conditions of carriage," Virgin says. The most pertinent of those conditions is the ban on behaving "... in a manner which would be considered by a reasonable person to be offensive, or in a manner which might cause discomfort, distress, offence or injury to another person," among others.
Qantas agrees: "The ability to recline in your seat is something all our customers value, and we would not look to implement any measures to restrict that. We have invested significantly in passenger comfort over the years and our seats are designed to maximise space for each passenger. Further, as part of our onboard service, we ensure each passenger is sitting upright during the meal service in order to ensure each customer has ample space. Qantas would not permit attachments such as the Knee Defender to aircraft seats, and in any event such attachments would need to undergo stringent reviews to ensure they comply with Australian safety regulations in the first instance before being considered."
The Civil Aviation Safety Authority hasn't banned them, but "anything that impacts the safe operation of the aircraft you definitely cannot and should not do," a spokesman said. "It appears on the surface that the Knee Defender may not, so it's not a matter for CASA. But we certainly encourage people to not do anything without talking to the airline."
Perhaps a good strategy is to remember that when it comes to cattle class, we're all in it, claustrophobically together. And with a little courtesy, things might just be a modicum more pleasant. For everyone. (What a concept!)
Etiquette expert Anna Musson (who described the Knee Defender as "obnoxious"), says there are "definitive rules about this, and we would all get along beautifully if everyone observed them." In her new book, Etiquette Secrets, Musson dedicates a whole section to flying manners. But the issues surrounding seatbacks, she says, are a particular bugbear.
"These rules are indisputable: You do not recline your seat if it is a less-than-three-hour flight," she says. "Particularly on the busiest route in the air, Sydney-Melbourne, just don't.
"If it is more than three hours, you may recline your seat, but wait till after meal service. If you know full well that the person behind you is still eating, do not recline your seat."
And finally, she adds, "You may be feeling very cramped, but so is everyone else. If you don't need to recline it all the way, don't. Sometimes just a little bit is enough to move your legs."
Traveller would like to add our own:
Check out who's behind you. If they're an AFL ruckman-sized human, perhaps resist your urge to hit the recline button. Will you really be that much more comfortable? And is your comfort that much more important than theirs?
Even if they're not above-average height, take a glance back before you recline to make sure they're not leant over and you're not going to break their nose, or their laptop.
And finally, maybe communicate; you know, like you do on the ground. Give a little warning to the person behind. Ask if they mind if you recline. A bit of humanity goes a long way – even at 30,000 feet.
What do you think the rules of reclining should be? Post your comments below.