Boeing launched the 787-10, the largest Dreamliner, at the Paris Air Show in June 2013, with commitments from Singapore Airlines and United. Boeing simply added two fuselage plugs to a proven design, and it shares 95 percent of that design with the 787-9. Range falls a little, but cost per seat falls further. That trade suits busy routes. Boeing aimed it at airlines that fill every seat.
Only the North Charleston plant in South Carolina builds it, because the mid-fuselage section is too long to ship inside the Dreamlifter transport aircraft. That single-site constraint is unusual for a Boeing program. The first aircraft rolled out in February 2017, flew on March 31, 2017, and Singapore Airlines began service in April 2018 on routes to Osaka. Production has stayed in South Carolina ever since.
With about 340 seats in two classes and roughly 11,700 kilometers of range, the -10 sits between the 787-9 and the 777-300ER. It suits dense medium-long-haul trunk routes rather than ultra-long flying. United, Etihad, KLM, British Airways and EVA Air fly it. It offers the lowest seat-mile costs of any 787, and sales exceed 200 aircraft. It has become the value play of the whole Dreamliner family.