Boeing 720: short‑range derivative of the 707 jet airliner

Design and characteristics

The 720 is distinguished from the 707 primarily by a shortened fuselage and weight‑saving modifications to wings and structure. It is a four‑engine jet that was offered with two powerplant families: early examples used Pratt & Whitney JT3C turbojets, and later versions were equipped with more efficient JT3D turbofans. Typical cabin arrangements were single‑aisle seating suitable for short to medium sectors. The aircraft featured tricycle landing gear, a pressurized cabin, and the aerodynamic layout common to first‑generation jet airliners.

• Engines: JT3C turbojets (original) and JT3D turbofans (720B).
• Configuration: narrow‑body, single aisle; four wing‑mounted engines.
• First flight / service: November 1959; entered airline service in 1960.
• Production: 154 aircraft built.

Development and variants

Boeing designed the 720 to capture traffic on shorter routes where the 707’s longer range and higher operating weight were unnecessary. The initial model carried the original turbojet engines. Responding to demand for better fuel economy and quieter operation, Boeing introduced the 720B variant fitted with Pratt & Whitney JT3D turbofan engines; many original 720s were later modified to 720B standard. The commonality with the 707 meant the 720 could be certified and fielded rapidly and inexpensively relative to an entirely new airframe.

Operational use and legacy

The 720 served with a number of airlines on domestic and regional international routes during the 1960s and into the following decades. Its role as a medium‑range airliner was gradually taken over by subsequent designs such as the Boeing 727 and later narrow‑body jets, which offered improved economics, higher capacity, or better short‑field performance. Despite a modest production run, the 720 contributed to Boeing’s early jetliner lineup by filling a specific market niche and by leveraging parts commonality to limit development expense.

Notable distinctions

Key points that distinguish the 720 include its shorter fuselage compared with the 707, the existence of the turbofan‑equipped 720B upgrade, and its status as a transitional design that bridged the gap between first‑generation long‑range jets and the emerging family of medium‑capacity airliners. For further technical summaries and historical overviews see the Boeing 720 general page: Boeing 720 overview, the parent model Boeing 707, airline service histories airline operations, the original turbojet type Pratt & Whitney JT3C and the turbofan upgrade Pratt & Whitney JT3D.