Getting a good night's sleep on a long haul flight isn't easy.

The standard 17 inch seats have many tossing and turning.

But a new study for European plane maker Airbus reveals that just one extra inch improved in-flight sleep quality by more than 50 percent.

And now Airbus, which has long provided a standard 18 inch seat on economy long haul flights, is calling on the rest of the industry to follow suit.

Kevin Keniston is Head of Passenger Comfort.

SOUNDBITE: Kevin Keniston, Head of Passenger Comfort, Airbus, saying (English):

"Let's make the flying experience a good one and the 18 inch wide seat allows you to have a good level of passenger comfort throughout that flight and as our research has just shown if you want to sleep during the flight you're going to have a much better night's sleep as well."

Many airlines have stuck to a model that dates back to the 1960s when there were few long-haul flights.

But over the years waistlines have grown.

The average movie theatre seat in the United States is 22 inches and standard seating at the UK's new Wembley stadium is 19.7"

SOUNDBITE: Unidentified passenger, saying (English):

"It would be more comfortable to have a bit more width."

SOUNDBITE: Unidentified passenger, saying (English):

"When you fly to Bangkok or China it's just too small."

The Airbus A380 is the world's largest jetliner.

But despite aggressive marketing, sales of the 525 seat double decker have been disappointing.

Many airlines are looking for narrower, lighter, twin engine models like Airbus' A350.

Airbus, though, still believes in the A380.

SOUNDBITE: Kevin Keniston, Head of Passenger Comfort, Airbus, saying (English):

"We see massive growth in long haul travel, we see the number of mega cities appearing around the world growing from 29 today to around 42 in 20 years time and the best aircraft to serve those markets is the A380.

Airbus customers may need convincing.

It's only sold 259 A380s and hasn't had any new orders so far this year.