European planemaker Airbus has dismissed US rival Boeing’s continued use of 17-inch seats on its long-haul economy planes as “substandard” and has called for an industry minimum of 18-inches, part of an increasingly bitter row that is likely to dominate talks with customers at this week’s Dubai Airshow.

“We believe the future of comfort in long haul is actually in jeopardy here,” Kevin Keniston, director of passenger comfort at Airbus, said at a press conference on Saturday ahead of the Dubai Airshow.

Airbus this month called for an industry standard that would provide for a seat at least 18 inches wide in economy cabins and criticised US rival Boeing who said it should be for airlines to decide and it was pushing ahead with continuing to offer 17-inch seats, a minimum standard which was set in the 1950s.

“More worryingly we see that standard being maintained for future Boeing products and basically what we are saying now is that is substandard comfort for economy passengers.

“Some of those aircraft are going to be delivered in the 2020s. If those aircraft are delivered with a substandard comfort standard you potentially are in a situation where in 2040 and beyond we will still be flying in a 17-inch standard.

“When did the 17-inch standard come in? It was in the 1950s, so 90 years and there has been no progress in terms of comfort standard and this is why we are doing this campaign... We don’t believe 1950 standard is acceptable,”

The dispute comes as planemakers vie to sell ever-larger versions of their twin-engined long-distance aircraft, with potentially record orders expected at the Dubai Airshow this week.

How the back of the plane is laid out - particularly whether seating is 9 or 10 abreast - is central to the economic performance claims being made for new 'mini-jumbo' jet designs.

Boeing says its revamped "777X" will hold 406 people based on economy seats over 17 inches wide and set out 10 in each row.

Airbus says the competing version of its A350 will carry 350 people in 18-inch-wide economy seat laid out 9 abreast.

Plane giants often trade blows on technical matters through advertising in the trade press. Now, Airbus is appealing directly to the public ahead of the Dubai Airshow, where the 777X is expected to dominate with over 100 orders.

It recently previewed what may be the start of a new ad war by showing financiers a slide illustrating three people squashed together at a restaurant, titled "Would You Accept This?"

"Boeing is proposing long-distance flying in seats narrower than regional turbo-props," said Airbus sales chief John Leahy.

As diets change, people get bigger but plane seating has not radically changed.

Between the early 1970s, when the Boeing 747 jumbo defined modern long-haul travel, and the turn of the century, the weight of the average American 40- to 49-year-old male increased by 10 percent, according to US Health Department Data.

The waist of the average 21st-century American male is 39.7 inches, according to US health statistics, which equates to a diameter of 12.6 inches. This leaves 2 inches either side in many plane seats, which are narrower than at an average cinema. The average theatre seat is now also currently 22 inches, Airbus said.

Airbus says that is not enough for long-haul travel and says its rival is sticking to a seat concept from the 1950s, when the average girth of the newly christened 'jet set' was narrower.

Airbus says it has commissioned research suggesting an extra inch in seat width improves sleep quality by 53 percent.

Boeing disputes Airbus's figures on seat measurements and says it is not up to manufacturers to step into decisions on how airlines balance fares and facilities. It also says research shows cabin experience depends on more than the width of a seat.

"It really comes down to providing flexibility to airlines and allowing them to do the things that they believe they need to do to be successful," said Boeing cabins expert Kent Craver.

"They don't want us to dictate to them what makes them profitable. They know their business better than anyone else."

For flyers it is about more elbow room, but for suppliers it is increasingly an issue that could affect earnings.

Behind the dispute is a race for plane orders with at least $700 billion of estimated business at list prices in coming decades, enough to tip the scales of U.S. and European exports.

As Reuters first reported in July, seat layout is exactly what drives the battle between the latest jets.

Both Airbus and Boeing claim 20 percent better efficiency per seat in their latest twin-engined long-haul designs than the market leader in that segment, the 365-seat Boeing 777-300ER.

Boeing's performance claims depend in part on comparing the 10-abreast 777X with an original 9-abreast 777 design. The gain in unit costs is blunted compared with 10-abreast now in use.