Boeing 737

The Boeing 737 is a highly successful American narrow-body aircraft.

It is produced by Boeing at its factory in Renton, Washington. This twinjet was originally developed to supplement the Boeing 727 on short and thin routes. A "thin route" refers to a flight path with less passenger demand. The aircraft is designed to be efficient for short-haul travel. It has become one of the most important tools in modern aviation history.

Designing the 737 involved significant engineering changes from its initial concept.

In 1964, the preliminary design featured engines mounted on the aft fuselage. It also used a T-tail design and five-abreast seating. However, engineer Joe Sutter moved the engines to the wings. This change lightened the aircraft structure. It also made it easier to fit six-abreast seating in the fuselage.

By mounting the engine nacelles directly under the wings, engineers could use shorter landing gear. This lowered the fuselage to improve passenger and baggage access. Moving the engines also allowed the horizontal stabilizer to be attached to the fuselage instead of a T-tail.

To speed up development, Boeing used 60% of the existing 727's systems and structure.

The fuselage width was kept at 148 inches. This specific width allowed for six seats across, which gave Boeing an advantage over competitors. The 737-100 made its first flight in April 1967. It entered service with Lufthansa in February 1968. Lufthansa was the first non-American airline to launch a new Boeing aircraft. The longer 737-200 entered service shortly after in April 1968. This model was more widely preferred by airlines than the smaller -100 version.

The aircraft has evolved through four distinct generations.

The first generation is the "Original" series, which includes the 737-100 and 737-200. These models used Pratt & Whitney JT8D low-bypass turbofan engines. The second generation is the "Classic" series, launched in 1980. It includes the -300, -400, and -500 variants. These used more fuel-efficient CFM56-3 high-bypass turbofans. The third generation is the "Next Generation" or NG, introduced in 1997. The NG variants, such as the -800, feature larger wings and upgraded glass cockpits. The fourth generation is the 737 MAX, which entered service in 2017.

These models use improved CFM LEAP-1B high-bypass turbofans.

Different variants offer various capacities for different needs.

The original models carried between 85 and 130 passengers. The Classic series increased this to 110 to 168 seats. The Next Generation models can carry between 108 and 215 passengers. Finally, the 737 MAX can accommodate between 138 and 204 people. Beyond commercial travel, Boeing produces Boeing Business Jet versions. The aircraft is also used for military purposes. For example, the C-40 Clipper and the P-8 Poseidon are military models based on the 737 design.

The 737 has achieved massive commercial success.

A total of 17,313 Boeing 737s have been ordered. Of those, 12,452 have been delivered. For a long time, it was the best-selling commercial aircraft in the world. It held this title until the Airbus A320 family surpassed it in October 2019. However, the 737 maintained the lead in total deliveries until September 2025. By 2013, the global 737 fleet had completed more than 184 million flights. This represents over 264 million block hours of flight time.

While successful, the aircraft has faced competition and challenges.

Initially, the main competitor was the McDonnell Douglas DC-9. This was later followed by the MD-80 and MD-90 derivatives. The 737 MAX was specifically designed to compete with the Airbus A320neo. The 737 MAX faced a significant period where it was grounded worldwide. This grounding occurred between March 2019 and November 2020 following two fatal crashes. Despite these challenges, the 737 remains a central part of the global aviation system. It connects people and goods across many different types of routes.