From the program's start, Boeing had considered building ultra-long-range variants.
Early plans centered on a 777-100X proposal, a shortened variant of the -200 with reduced weight and increased range, similar to the 747SP.
However, the -100X would have carried fewer passengers than the -200 while having similar operating costs, leading to a higher cost per seat.
By the late 1990s, design plans shifted to longer-range versions of existing models.

In March 1997, the Boeing board approved the 777-200X/300X specifications: 298 passengers in three classes over 8,600 nmi (15,900 km) for the 200X and 6,600 nmi (12,200 km) with 355 passengers in a tri-class layout for the 300X, with design freeze planned in May 1998, 200X certification in August 2000, and introduction in September and in January 2001 for the 300X. The 1.37 m (4 ft 6 in) wider wing was to be strengthened and the fuel capacity enlarged, and it was to be powered by simple derivatives with similar fans.
GE was proposing a 454 kN (102,000 lbf) GE90-102B, while P&W offered its 436 kN (98,000 lbf) PW4098 and R-R was proposing a 437 kN (98,000 lbf) Trent 8100.

Rolls-Royce was also studying a Trent 8102 over 445 kN (100,000 lbf).

Boeing was studying a semi-levered, articulated main gear to help the take-off rotation of the proposed -300X, with its higher 324,600 kg (715,600 lb) MTOW.

By January 1999, its MTOW grew to 340,500 kg (750,000 lb), and thrust requirements increased to 110,000–114,000 lbf (490–510 kN).

A more powerful engine in the thrust class of 100,000 lbf (440 kN) was required, leading to talks between Boeing and engine manufacturers.
General Electric offered to develop the GE90-115B engine, while Rolls-Royce proposed developing the Trent 8104 engine.
In 1999, Boeing announced an agreement with General Electric, beating out rival proposals.
Under the deal with General Electric, Boeing agreed to only offer GE90 engines on new 777 versions.

On February 29, 2000, Boeing launched its next-generation twinjet program, initially called 777-X, and began issuing offers to airlines.
Development was slowed by an industry downturn during the early 2000s.
The first model to emerge from the program, the 777-300ER, was launched with an order for ten aircraft from Air France, along with additional commitments.
On February 24, 2003, the -300ER made its first flight, and the FAA and EASA (European Aviation Safety Agency, successor to the JAA) certified the model on March 16, 2004.
The first delivery to Air France took place on April 29, 2004.
The -300ER, which combined the -300's added capacity with the -200ER's range, became the top-selling 777 variant in the late 2000s, benefitting as airlines replaced comparable four-engine models with twinjets for their lower operating costs.

The second long-range model, the 777-200LR, rolled out on February 15, 2005, and completed its first flight on March 8, 2005.
The -200LR was certified by both the FAA and EASA on February 2, 2006, and the first delivery to Pakistan International Airlines occurred on February 26, 2006.
On November 10, 2005, the first -200LR set a record for the longest non-stop flight of a passenger airliner by flying 11,664 nautical miles (21,602 km) eastward from Hong Kong to London.
Lasting 22 hours and 42 minutes, the flight surpassed the -200LR's standard design range and was logged in the Guinness World Records.

The production freighter model, the 777F, rolled out on May 23, 2008.
The maiden flight of the 777F, which used the structural design and engine specifications of the -200LR along with fuel tanks derived from the -300ER, occurred on July 14, 2008.
FAA and EASA type certification for the freighter was received on February 6, 2009, and the first delivery to launch customer Air France took place on February 19, 2009.
From the program's start, Boeing had considered building ultra-long-range variants. Early plans centered on a 777-100X proposal, a shortened variant of the -200 with reduced weight and increased range, similar to the 747SP. However, the -100X would have carried fewer passengers than the -200 while having similar operating costs, leading to a higher cost per seat. By the late 1990s, design plans shifted to longer-range versions of existing models.
In March 1997, the Boeing board approved the 777-200X/300X specifications: 298 passengers in three classes over 8,600 nmi (15,900 km) for the 200X and 6,600 nmi (12,200 km) with 355 passengers in a tri-class layout for the 300X, with design freeze planned in May 1998, 200X certification in August 2000, and introduction in September and in January 2001 for the 300X. The 1.37 m (4 ft 6 in) wider wing was to be strengthened and the fuel capacity enlarged, and it was to be powered by simple derivatives with similar fans. GE was proposing a 454 kN (102,000 lbf) GE90-102B, while P&W offered its 436 kN (98,000 lbf) PW4098 and R-R was proposing a 437 kN (98,000 lbf) Trent 8100.
Rolls-Royce was also studying a Trent 8102 over 445 kN (100,000 lbf).
Boeing was studying a semi-levered, articulated main gear to help the take-off rotation of the proposed -300X, with its higher 324,600 kg (715,600 lb) MTOW.
By January 1999, its MTOW grew to 340,500 kg (750,000 lb), and thrust requirements increased to 110,000–114,000 lbf (490–510 kN).
A more powerful engine in the thrust class of 100,000 lbf (440 kN) was required, leading to talks between Boeing and engine manufacturers. General Electric offered to develop the GE90-115B engine, while Rolls-Royce proposed developing the Trent 8104 engine. In 1999, Boeing announced an agreement with General Electric, beating out rival proposals. Under the deal with General Electric, Boeing agreed to only offer GE90 engines on new 777 versions.
On February 29, 2000, Boeing launched its next-generation twinjet program, initially called 777-X, and began issuing offers to airlines. Development was slowed by an industry downturn during the early 2000s. The first model to emerge from the program, the 777-300ER, was launched with an order for ten aircraft from Air France, along with additional commitments. On February 24, 2003, the -300ER made its first flight, and the FAA and EASA (European Aviation Safety Agency, successor to the JAA) certified the model on March 16, 2004. The first delivery to Air France took place on April 29, 2004. The -300ER, which combined the -300's added capacity with the -200ER's range, became the top-selling 777 variant in the late 2000s, benefitting as airlines replaced comparable four-engine models with twinjets for their lower operating costs.
The second long-range model, the 777-200LR, rolled out on February 15, 2005, and completed its first flight on March 8, 2005. The -200LR was certified by both the FAA and EASA on February 2, 2006, and the first delivery to Pakistan International Airlines occurred on February 26, 2006. On November 10, 2005, the first -200LR set a record for the longest non-stop flight of a passenger airliner by flying 11,664 nautical miles (21,602 km) eastward from Hong Kong to London. Lasting 22 hours and 42 minutes, the flight surpassed the -200LR's standard design range and was logged in the Guinness World Records.
The production freighter model, the 777F, rolled out on May 23, 2008. The maiden flight of the 777F, which used the structural design and engine specifications of the -200LR along with fuel tanks derived from the -300ER, occurred on July 14, 2008. FAA and EASA type certification for the freighter was received on February 6, 2009, and the first delivery to launch customer Air France took place on February 19, 2009.
Boeing 777