Size really does matter when it comes to sleeping on a plane, according to a study by aircraft manufacturer Airbus.
Research by the European plane-maker has revealed that sleep quality improves by 53 per cent in an 18-inch (46-centimetre) seat compared to a 17-inch (43-centimetre) seat.
The study says that the time it takes to fall asleep in the one-inch (2.54-cm) wider seat improves by 14.7 per cent and that on average, passenger awakenings on a long-haul flight are reduced by 28 minutes.
Airbus head of passenger comfort Kevin Keniston said many airlines have stuck to the 17-inch seat that dates back to the 1950s, when there were few long-haul flights.
Airbus has called on airlines to have a standard 18-inch seat in its long-haul economy cabins.
“Over the years waistlines have grown," Mr Keniston said. “The average movie theatre seat in the United States is now 22 inches and the standard seating at the UK's new Wembley Stadium is 19.7.”
In Australia, passengers on the Indian Pacific train from Sydney to Perth enjoy a 19.3-inch standard seat on the 4352-kilometre journey.
Some airlines, including Qantas, now allow passengers to book emergency exit row seats or other seats that feature extra leg room. For an additional fee, of course.
The London Sleep Centre conducted the study for Airbus.
“All passengers experienced a deeper, less disturbed and longer night's sleep in the 18-inch seat," the centre's Dr Irshaad Ebrahim said.
“They went from one sleep stage to the next as you would expect them to do under normal circumstances. Whilst, in the narrower 17-inch seat the passengers were affected by numerous disturbances – which meant they rarely experienced deep restorative sleep.
“When it comes to flying long-haul in economy, an inch makes a huge difference on passenger comfort.”
Sleep physician Dr Maree Barnes, from the Sleep Health Foundation in Melbourne, said: “We are not only a more obese society than we were 50 years ago but we are also taller.
“For those reasons, a wider seat is going to make it more comfortable to travel and the more comfortable you are the more likely you are to sleep.
“The little bit of extra room gives you a chance to turn onto your side.”
To try to sleep on a plane, Dr Barnes suggests doing things you do at home to sleep.
“Get into a pair of pyjamas, put on blinkers to block out light, don't have a huge meal, alcohol, caffeine or even a cigarette just before you board because tobacco is a stimulant," she said.
“Alcohol initially makes you more relaxed but as it wears off it in fact becomes a stimulant.”
Airbus said that in the past five years the number of flights over 6000 nautical miles (13-plus flying hours) has increased by 70 per cent, from 24 to 41 a day.
“If the aviation industry doesn't take a stand right now [for wider seats] then we risk jeopardising passenger comfort into 2045 and beyond, especially if you take into account aircraft delivery timetables combined with expected years in service,” Mr Keniston said.
“Which means another generation of passengers will be consigned to seats which are based on outdated standards.”
But of course, business class passengers may think it's all a yawn – some already enjoy lie-flat seats that are up to 34 inches wide on long-haul flights.
Seat width in economy class (international flights)
Qantas: 17.5 inches
Jetstar: 18 inches
Virgin Australia: 17.5-18.5 inches
Air New Zealand: 17-18 inches
Emirates: 17-18 inches
Singapore Airlines: 18-19 inches
Thai Airways: 17-18 inches
Malaysia Airlines: 17-18 inches
Cathay Pacific: 17.5 inches
Etihad: 17.5 inches
United Airlines: 17 inches
Garuda Indonesia: 17 inches
AirAsia X: 16.5 inches