The next generation of massive fuel-efficient aircrafts is closer than ever to completion. Last week, Boeing announced the configuration for the 777-9, the first addition of Boeing 777X airplanes to be developed, which also includes a future 777-8 model. The Boeing 777X aircrafts will be the largest and most efficient twin-engine jets in the world.

Designs implement airline customer and supplier feedback and have significantly higher fuel ratings compared to the A350. The planes will consume 12 percent less fuel and cost 10 percent less to operate than competitor models. The Boeing 777X group has received requests for 320 airplanes from six airlines worldwide. Production will begin in 2017.

“It’s great to see the airlines and industry team side-by-side with us as we achieve this important milestone,” said Bob Feldmann, vice president and general manager of the 777X program, Boeing Commercial Airplanes. “The team has followed a disciplined process to complete all of the requirements for this stage of the program.”

According to CNN, passengers can expect that the new aircrafts will look and feel nothing like a standard plane. The 777-9 will have 12-foot wingtips that hinge and fold-up so that its wingspan can shorten during taxi. At its fullest, the wingspan measures across 235 feet and 5 inches—the widest of any Boeing aircraft to date.

Travelers can rest assured that interior cabin space will offer improved passenger comfort. The 777-9 model will fit approximately 400 passengers, which is 34 more than the Airbus A350-1000. The cabin will also be built 16 inches wider than the Airbus model. Economy-class seats could measure up to 18 inches wide, and window seats will be placed at eye-level height next to windows that measure 15 percent larger than other airlines.

Emirates Airlines will likely become a customer of Boeing 777x aircrafts. The Dubai-based carrier is the world’s largest operator of the 777 and is also the only carrier to operate all six 777 models.