In tandem with the development of the third generation Boeing 777X, Boeing worked with General Electric to offer a 2% improvement in fuel efficiency to in-production 777-300ER aircraft.
General Electric improved the fan module and the high-pressure compressor stage-1 blisk in the GE-90-115 turbofan, as well as reduced clearances between the tips of the turbine blades and the shroud during cruise.
These improvements, of which the latter is the most important and was derived from work to develop the 787, were stated by GE to lower fuel burn by 0.5%.
Boeing's wing modifications were intended to deliver the remainder.
Boeing stated that every 1% improvement in the 777-300ER's fuel burn translates into being able to fly the aircraft another 75 nmi (139 km; 86 mi) on the same load of fuel, or add ten passengers or 2,400 lb (1,100 kg) of cargo to a "load limited" flight.

In March 2015, additional details of the improvement package were unveiled.
 The 777-300ER was to shed 1,800 lb (820 kg) by replacing the fuselage crown with tie rods and composite integration panels, similar to those used on the 787.
The new flight control software was to eliminate the need for the tail skid by keeping the tail off the runway surface regardless of the extent to which pilots command the elevators.
Boeing was also redesigning the inboard flap fairings to reduce drag by reducing pressure on the underside of the wing.
The outboard raked wingtip was to have a divergent trailing edge, described as a "poor man's airfoil" by Boeing; this was originally developed for the McDonnell Douglas MD-12 project.
Another change involved elevator trim bias.
These changes were to increase fuel efficiency and allow airlines to add 14 additional seats to the airplane, increasing per seat fuel efficiency by 5%.

Mindful of the long time required to bring the 777X to the market, Boeing continued to develop improvement packages which improve fuel efficiency, as well as lower prices for the existing product.
In January 2015, United Airlines ordered ten 777-300ERs, normally costing around US$150 million each but paid around US$130 million, a discount to bridge the production gap to the 777X.  The roll-out of the prototype 777X, a 777-9 model, occurred on March 13, 2019.

As of 2019, Boeing lists prices for the 777-200ER, -200LR, 777F, -300ER, 777-8, and 777-9 variants.
The -200ER is the only Classic variant remaining available.
In tandem with the development of the third generation Boeing 777X, Boeing worked with General Electric to offer a 2% improvement in fuel efficiency to in-production 777-300ER aircraft. General Electric improved the fan module and the high-pressure compressor stage-1 blisk in the GE-90-115 turbofan, as well as reduced clearances between the tips of the turbine blades and the shroud during cruise. These improvements, of which the latter is the most important and was derived from work to develop the 787, were stated by GE to lower fuel burn by 0.5%. Boeing's wing modifications were intended to deliver the remainder. Boeing stated that every 1% improvement in the 777-300ER's fuel burn translates into being able to fly the aircraft another 75 nmi (139 km; 86 mi) on the same load of fuel, or add ten passengers or 2,400 lb (1,100 kg) of cargo to a "load limited" flight.
In March 2015, additional details of the improvement package were unveiled.  The 777-300ER was to shed 1,800 lb (820 kg) by replacing the fuselage crown with tie rods and composite integration panels, similar to those used on the 787. The new flight control software was to eliminate the need for the tail skid by keeping the tail off the runway surface regardless of the extent to which pilots command the elevators. Boeing was also redesigning the inboard flap fairings to reduce drag by reducing pressure on the underside of the wing. The outboard raked wingtip was to have a divergent trailing edge, described as a "poor man's airfoil" by Boeing; this was originally developed for the McDonnell Douglas MD-12 project. Another change involved elevator trim bias. These changes were to increase fuel efficiency and allow airlines to add 14 additional seats to the airplane, increasing per seat fuel efficiency by 5%.
Mindful of the long time required to bring the 777X to the market, Boeing continued to develop improvement packages which improve fuel efficiency, as well as lower prices for the existing product. In January 2015, United Airlines ordered ten 777-300ERs, normally costing around US$150 million each but paid around US$130 million, a discount to bridge the production gap to the 777X.  The roll-out of the prototype 777X, a 777-9 model, occurred on March 13, 2019.
As of 2019, Boeing lists prices for the 777-200ER, -200LR, 777F, -300ER, 777-8, and 777-9 variants. The -200ER is the only Classic variant remaining available.
Boeing 777