Airbus is evaluating changes to the Airbus A350-1000 cabin that would allow airlines to fit in around an additional 20 seats.

The cabin modifications would be ready toward the end of the decade, according to Executive Vice-President Programs Didier Evrard, who is also still running the A350 program. Airbus does not change the basic layout of the aircraft at entry into service. That is designed for 369 seats in a two-class configuration. Optimizing the integration and design of galleys and lavatories are issues Airbus is currently looking into to facilitate the increase.

Adding another 20 seats would move the aircraft closer in capacity to Boeing’s 777-9X which is targeted to seat 400 passengers—the shorter -8X is designed for 350 in Boeing’s nominal layout.

Evrard did not say which airlines in particular are behind the studies. However, Airbus is keen to win back a large Emirates order for the A350. The airline canceled an order for 70 aircraft last year. It is in the process of repeating the competition, but now includes the Boeing 787-10. According to Boeing, the -10 has space for 323 passengers.

Cabin changes could conceivably be moved back into the smaller -900 at some stage, increasing that airplane’s seating capacity too. The Airbus standard layout in two classes currently defines the aircraft as a 315-seater.

Airbus has been playing with the idea of developing a further stretch of the A350 beyond the -1000, which it acknowledges would be technically feasible. However, Chief Operating Officer-Customers John Leahy has been downplaying the idea. Earlier this week he said that he did not believe the 400-seat market is big enough to justify another derivative. He argued that Boeing only stretched the 777X in order to achieve seat-mile costs comparable to the A350-1000, rather than because of true market demand.

Airbus been consistently raising maximum seating capacity for its narrow-bodies with the A321 now going up to 240 seats, and the A320, to 189. But Leahy said the trend to larger capacity witnessed in the short-haul market was not necessarily as visible in the long-haul segment.

Separately, Airbus was successful in further melting down the backlog of its unwanted A350-800. The manufacturer now has 16 aircraft left on firm order for the type, eight each from Asiana and Aeroflot. Hawaiian has switched over to the A330-800, while Yemenia moved an order for ten A350-800s to the larger -900.