767-400ERX, a model that only exists on drawings. In the 1990s,Facing the A330-200 released by Airbus, Boeing designed the 767-400ER ERX in order to improve the winning rate of the 767-400ER in this competition, and it was equipped with GE GEnx, which was still on the drawing at that time, reducing noise by 25% and fuel consumption by 20%. At the same time, the structural strength is improved on the original basis, so that the volume of the fuel tank can be increased, and the longest voyage can reach 12,000 kilometers. On the basis of the original wing, carbon fiber composite material is added, which makes the wing more flexible and reduces the air resistance, and the air speed is 15% higher than that of 767-400ER. However, such a plan caused the global aviation industry to fall into a trough due to the September 11th terrorist attacks in 2001, and the extremely radical Yellowstone Project Y2 (787) launched by Boeing later made this model never come out again.