or 747-400. In aviation circles, a more specific model designation is sometimes used where the last two digits of the series designator are replaced by the two-digit, alpha-numeric Boeing customer code, for example, 747-121, representing a 747-100 originally ordered by Pan American World Airways (Boeing customer code 21) or 737-7H4, representing a 737-700 originally ordered by Southwest Airlines (Boeing customer code H4). Codes do not change for aircraft transferred from one airline to another. Unlike other models, the 787 uses a single digit to designate the series, for example, 787-8. This convention was followed in the development of the newest version of the 747, the 747-8, along with the 737 MAX and 777X series. Additional letters are sometimes appended to the model name as a suffix, including "ER" to designate an "extended range" version, such as the 777-300ER, or "LR" to designate a "long range" version, for example 777-200LR. Other suffix designators include "F" for "freighter" (747-400F), "C" for "convertible" aircraft that can be converted between a passenger and freighter configuration (727-100C), "SR" or "D" for "short range" and "domestic" (747-400D, 747SR), and "M" for "combi" aircraft that are configured to carry both passengers and freight at the same time (757-200M, 747-400M). Passenger aircraft that are originally manufactured as passenger aircraft and later converted to freighter configuration by Boeing carry the suffix "BCF" designating a Boeing converted freighter (747-400BCF). Aircraft in production or development Orders and deliveries The table below lists only airliners from the jet era. Data from Boeing through end of December 2021 Discontinued aircraft Gallery Specialty and other aircraft Airlines commonly order aircraft with special features or options, but Boeing builds certain models specifically for a particular customer. The Boeing 707-138B was a shortened-fuselage, long-range model only sold to Qantas. The Boeing 757-200M was a single-example model built for Royal Nepal Airlines (now called Nepal Airlines). This plane could be converted between passenger and freighter configuration. It was launched by Royal Nepal Airlines in 1986 and delivered two years later. Boeing 747 The Shuttle Carrier Aircraft The Boeing 747 Large Cargo Freighter (named the Dreamlifter) is a wide-body cargo aircraft. The 747SP production resumed nearly four years after the supposedly final 747SP was built, to manufacture one aircraft for the United Arab Emirates. It had a cockpit crew of two instead of the three-crew layout of other 747SPs. Two Boeing VC-25s were built for the US Air