Largest of the 767s, the 767-400ER lengthened the fuselage and added raked wingtips later adopted on the 787. Boeing flew it in 1999, and in practice only Delta Air Lines and United Airlines ordered the model. Two General Electric CF6-80C2B8F engines seat 245 in usual layouts and up to 375 at capacity, across roughly 10,415 km at cruise speeds near 851 km/h. The twin measures 61.37 metres long on a 51.92-metre span, climbs to a 13,100-metre ceiling, and grosses up to 204,120 kg. A slim order book kept the fleet small, and production has since ended. Controllers designate it B764, under the IATA code 764.
The Boeing 767-400ER typically seats 245 passengers in a three-class configuration. In a two-class layout, it can carry around 304 passengers. At 61.4 m, it is the longest member of the 767 family, stretched 6.4 m beyond the 767-300ER. The cabin retains the 2-3-2 economy layout but with more rows due to the extended fuselage.
The Boeing 767-400ER has a maximum range of approximately 10,415 km (5,625 nautical miles). Despite being the newest 767 variant, its range is shorter than the 767-300ER (11,065 km) due to the higher weight of the stretched fuselage without proportionally increased fuel capacity. The aircraft uses General Electric CF6-80C2B8F engines and features raked wingtips, the first Boeing commercial aircraft to use this design.
The 787-8 Dreamliner effectively replaced the 767-400ER, offering significantly better range (13,620 km vs 10,415 km) and approximately 20% lower fuel consumption per seat. The 787 uses an all-composite fuselage and more advanced engines. The 767-400ER has a wider cabin at 4.72 m versus the 787's 5.49 m, but the 787's composite fuselage allows for larger windows and higher cabin pressure for better passenger comfort.
The 767-400ER is the longest 767 variant and the only one with raked wingtips, making identification straightforward. The raked wingtips give the wing a more swept appearance compared to the conventional rounded wingtips on the 767-200 and 767-300. The stretched fuselage has more window rows than the 767-300, and the overall proportions appear more elongated.
Only 38 Boeing 767-400ERs were delivered, making it one of the rarest wide-body types in commercial aviation. Delta Air Lines received 21 aircraft, and Continental Airlines (now United Airlines) received 16, with one going to a private customer. The type was launched in 2000 but quickly lost market appeal as the Boeing 787 Dreamliner program was announced. Delta continues to operate its fleet, making them the primary operator of this rare variant.