[article] In 2020, Boeing says it will start deliveries of a new airplane, which is called 777x for now, that will be 12 percent more fuel efficient than its competition. That would bring huge savings to airlines in reduced fuel costs. The plane is based, as the name suggests, on Boeing’s large 777 airliner. To get the fuel savings, Boeing is using the new GE9X engine from GE Aviation. It will also have composite wings that are longer than the ones on the current 777. Longer wings are known to improve efficiency, but pose a problem for negotiating airports. One solution is to add vertical winglets, which has much the same effect. With the 777x, Boeing has opted for longer wings that fold up when the plane is on the ground, shortening the wingspan by just over 6 meters. Boeing has received 259 orders for the airplane.