United Airlines is facing an unusual problem as Boeing’s long-delayed 737 Max 10 moves closer to federal certification: hundreds of expensive lie-flat seats bought for the aircraft have been sitting in storage for years, and they may no longer fit the airline’s current plans.
The dilemma dates back to August 2018, when Scott Kirby, then president of United Airlines and now its chief executive, outlined an ambitious vision for the new aircraft at an aviation conference in Denver. United planned to use the largest member of Boeing’s bestselling 737 Max family on profitable transcontinental routes, with a premium cabin featuring lie-flat seats.
The aircraft was originally expected to enter service in 2020.
More than six years after that target, the Max 10 has yet to receive certification from U.S. regulators. Boeing and several of its airline customers now expect approval to come soon, setting the stage for United to finally take delivery of an aircraft whose planned interior has evolved considerably since the seats were first purchased.
“We got a bunch of lie-flat seats that we don’t know what to do with,” Kirby told CNBC during an interview earlier this month at Newark Liberty International Airport in New Jersey. “They don’t fit on other airplanes.”
The problem illustrates how prolonged delays in aircraft certification can create complications well beyond Boeing’s production schedules. Airlines that ordered the Max 10 years ago have had to adjust fleet plans, routes and cabin configurations while waiting for the aircraft to become available.
United has not revealed exactly how it intends to configure its Max 10 aircraft or which routes the planes will serve. The airline's original plans were also developed before United introduced a premium economy section, meaning the cabin strategy envisioned in 2018 is no longer necessarily the one that will be installed on the aircraft.
The Max 10 has been held up partly by engineering changes required for Boeing's anti-icing system. The delays have also unfolded as Boeing has faced intense regulatory and public scrutiny following years of safety, manufacturing and quality-control problems involving the 737 Max program.
The certification process has affected other members of the Max family as well. The 737 Max 7, the smallest version of the aircraft, received federal approval earlier this month. Southwest Airlines, its largest customer, expects to begin flying the model during the first half of 2027.
United, meanwhile, has already taken steps to adapt its fleet to changing market demands while waiting for Boeing.
The airline recently equipped a subfleet of Airbus A321neo aircraft with 20 of its newly designed Polaris suites, along with premium economy seating and other updated cabin products. United calls the aircraft the “Coastliner,” reflecting its intended role on transcontinental routes.
That move has given United another option for premium-heavy flights, but it has not solved the problem of the Max 10 seats sitting in storage. The Airbus A321neo and Boeing 737 Max 10 have different cabin dimensions and installation requirements, meaning the seats designed for one aircraft cannot simply be transferred to the other.
United must therefore determine how much of its original Max 10 interior concept remains viable and how much must be redesigned.
The stakes are significant. United has ordered 167 Boeing 737 Max 10 aircraft, according to its most recent quarterly filing, making the model an important part of the airline's future narrow-body fleet.
The airline expects to receive its first Max 10 aircraft in the summer of 2027.
By then, the aircraft will have arrived years later than originally anticipated, and United's business strategy will have changed along with the industry. The airline's growing emphasis on premium seating, transcontinental travel and higher-yielding cabins means the Max 10 could eventually play a different role from the one envisioned when Kirby first described the aircraft in 2018.
For now, however, United's immediate challenge is more practical: deciding what to do with hundreds of lie-flat seats that were purchased for an aircraft that has spent years waiting for regulatory approval.
“We got a bunch of lie-flat seats that we don’t know what to do with,” Kirby said.
The long-awaited arrival of the Max 10 may finally give United an answer.