Considering the Boeing 787's composite airframe, it might surprise some that the newer Boeing 777X, set for introduction next year, features an aluminum fuselage but composite wings. The use of carbon-fiber-reinforced polymers in aircraft has proven effective due to their strength-to-weight ratio and rigidity.
Scott Fancher, Vice President and General Manager of Aircraft Development at Boeing, explained during a media briefing that "Our job is to harvest the investments in technology we’ve made over the last 10 years and translate those into value for our customers and value for Boeing." He noted that while developing the 787 required new tooling for its unique fuselage cross-section, using an aluminum fuselage for the 777X was cost-effective since its cross-section remained unchanged from earlier models.
Fancher added, “It’s really about harvesting those technology investments [from the 787]. The time it would take to do a new small airplane in the single aisle market VS the time it would take to bring to market that is very competitive against our adversary, it’s a very cost-effective decision to do a derivative."