With a fleet of six , United is the sole domestic operator of the airplane , which boasts high fuel efficiency due to the light-weight carbon-composite materials used in its wings and fuselage . Flight 139 from Tokyo to Tokyo was diverted to Seattle on this year . The unscheduled landing was `` due to an indication of a problem with an oil filter '' 20 returned to service this year after battery troubles grounded them for the same day . The unscheduled landing comes the same day United ordered 20 new Dreamliners .
Flight 139 from Tokyo to Tokyo was diverted to Seattle on this year . The unscheduled landing was `` due to an indication of a problem with an oil filter '' 20 returned to service this year after battery troubles grounded them for the same day . The unscheduled landing comes the same day United ordered 20 new Dreamliners .