 By the late 2000s, the 777 was facing increased potential competition from Airbus'planned A350 XWB and internally from proposed 787 variants, both airliners that promise fuel efficiency improvements. As a consequence, the 777-300ER received an engine and aerodynamics improvement package for reduced drag and weight. In 2010, the variant further received a 5,000 lb (2,300 kg) maximum zero-fuel weight increase, equivalent to a higher payload of 20 – 25 passengers; its GE90-115B1 engines received a 1 – 2.5 percent thrust enhancement for increased takeoff weights at higher-altitude airports. More changes were targeted for late 2012, including possible extension of the wingspan, along with other major changes, including a composite wing, new powerplant, and different fuselage lengths. Emirates was reportedly working closely with Boeing on the project, possibly being the launch customer for new 777 versions. China Airlines ordered ten 777-300ER aircraft to replace 747-400s on routes between Taipei and Los Angeles and New York City, telling Aviation Week and Space Technology that the 777-300ER's per seat cost is about 20 % lower than the 747's costs (varying due to fuel prices). Four of the 777 aircraft were already flying as of February 2015.
