The Boeing numbering system for commercial airliners starts with the airplane's model number, e.g. 377 followed by a dash and three digits (two numbers) following the pattern Boeing xxx-scc. In general, since the Boeing 707, the model number takes the form of a 7 followed by a digit and then by another 7, e.g. 737.
The series number is a single digit (s), e.g. -200. The following two digits number (cc) is attributed according to the company to which the aircraft was first delivered. These two digits are called Boeing customer codes. For instance, a Boeing 767-300 delivered to Air Canada would take the designation "767-333" while a 777-200 delivered to American Airlines would take the designation "777-223". See List of Boeing customer codes for a more complete list.
Additional letters are sometimes used. These include, "ER" for an "extended range" version or "LR" for the "long range" version.
Current production
Product list and details (date information from Boeing)
Although aircraft are commonly ordered with features or options at the request of the ordering airline, there are certain models which have been built specifically for the customer.
The Boeing 707-138B was a shortened fuselage, long range model only sold to Qantas.
The Boeing 757-200 Combi was a single example model built for Royal Nepal Airlines (later renamed Nepal Airlines), though the engineering design of the freight door was subsequently used when UPS was the launch customer for the 757-200PF several years later.
The 747SP production line was re-opened nearly four years after the supposedly final 747SP was built. One aircraft was built for the United Arab Emirates. The cockpit, unlike that of other 747SP, had a crew of two instead of three.
Douglas, prior to its merger with McDonnell, built the DC-9-20 for Scandinavian Airlines. This model combined the fuselage of the DC-9-10 with the wings of a DC-9-30. No other airline ordered the aircraft.