Boeing 737
American narrow-body jet produced by Boeing since 1967.
Shougissime · CC BY-SA 4.0
The Boeing 737 is a narrow-body jetliner built by Boeing in Washington state. It was designed to handle short, low-demand routes where the larger Boeing 727 was less efficient. The aircraft uses the same fuselage width as the Boeing 707, allowing six seats across, and is powered by two Pratt & Whitney JT8D low-bypass turbofan engines mounted under the wings.
Boeing began studying the concept in 1964, aiming for a 50- to 60-seat plane for flights between 50 and 1,000 miles. Early designs placed engines on the rear fuselage with a T-tail, but engineer Joe Sutter moved them to the wings. This change lightened the structure, made six-abreast seating easier, and allowed a lower fuselage for better baggage and passenger access. The engine nacelles attach directly under the wings without pylons, shortening the landing gear. The horizontal stabilizer was mounted on the rear fuselage rather than as a T-tail. Wind tunnel tests found that a relatively thick engine attachment strut reduced drag at high speeds.
At the time, Boeing lagged behind competitors like the SE 210 Caravelle, BAC One-Eleven, Douglas DC-9, and Fokker F28. To speed development, Boeing reused 60% of the structure and systems from the 727, including its fuselage cross-section (148 inches wide), which came from the 707. The wing airfoil was based on the 707 and 727 but thicker, with modifications near the nacelles to cut drag at high Mach numbers. The JT8D-1 engine provided 14,500 pounds of thrust. The concept was presented in October 1964, but its complex high-lift devices raised concerns about maintenance and reliability.
The first 737 variant, the 737-100, flew in April 1967 and entered service with Lufthansa in February 1968. A stretched version, the 737-200, followed in April 1968. Over time, the 737 evolved through four generations. The first generation (737-100 and -200) used Pratt & Whitney JT8D engines and seated 85 to 130 passengers. The second generation, or 737 Classic (-300, -400, -500), launched in 1980 and entered service in 1984, with more efficient CFM56-3 high-bypass turbofans and seating for 110 to 168. The third generation, the 737 Next Generation (-600, -700, -800, -900), introduced in 1997, featured updated CFM56-7 engines, a larger wing, an upgraded glass cockpit, and seating for 108 to 215. The fourth generation, the 737 MAX (-7, -8, -9, -10), entered service in 2017 with CFM LEAP-1B engines and seats 138 to 204. Boeing Business Jet versions have been produced since the NG generation, along with military models.
As of July 2026, 17,507 Boeing 737s had been ordered and 12,654 delivered. It was the best-selling commercial aircraft until the Airbus A320 family overtook it in October 2019, though it led in total deliveries over the A320 until September 2025. Its early competitors were the McDonnell Douglas DC-9 and later the MD-80/MD-90. By 2013, the global 737 fleet had completed over 184 million flights and 264 million block hours. The 737 MAX, designed to rival the A320neo, was grounded worldwide from March 2019 to November 2020 after two fatal crashes.
The 737 was launched on February 1, 1965, with a $150 million development budget. Lufthansa became the launch customer on February 19, 1965, ordering 21 aircraft after Boeing assured the project would not be canceled. Lufthansa’s input increased seating to 100. On April 5, 1965, United Airlines ordered 40 737s, wanting a larger capacity than the 737-100. This led to a stretched version, the 737-200, with the fuselage extended 36 inches ahead of the wing and 40 inches behind it. The original short-body model became the 737-100.
- First flight
- April 9, 1967 (737-100)
- Manufacturer
- Boeing
- National origin
- United States
- Variants
- Four generations: Original, Classic, Next Generation, MAX
Lore & Background
The Boeing 737 was developed to complement the 727 on shorter routes where the 727 was less economical. Engineer Joe Sutter relocated the engines from the aft fuselage to the wings, lightening the structure and allowing six-abreast seating. The engines are mounted on pylons under the wings, which helped shorten the landing gear and lower the fuselage for improved access. The 737 reused about 60% of the 727's parts and systems, but it was a new design, not a derivative of the 727.
Reader's Guide
The Boeing 737 is significant as the best-selling commercial aircraft until October 2019, when it was surpassed by the Airbus A320 family in orders, though it maintained the lead in total deliveries until September 2025. Its four generations—Original, Classic, Next Generation, and MAX—introduced successive improvements in engines, seating capacity, and avionics. The 737 MAX was grounded worldwide between March 2019 and November 2020 following two fatal crashes.
Did You Know?
- The 737-100 received FAA certification for Category II approaches after its initial certification, but it was not the first aircraft to do so.
- The 737 MAX was grounded worldwide from March 2019 to November 2020 following two fatal crashes.
- The fuselage is manufactured in Wichita, Kansas, by Boeing spin-off Spirit AeroSystems, then moved by rail to Washington.
A Half-Century of Operational History
By March 2018, the ten-thousandth member of the family had entered service, a milestone spanning five decades of continuous production across four distinct generations: the Original, the Classic, the Next Generation, and the MAX. Yet this extraordinary commercial success exists alongside a safety record that, while statistically small relative to the sheer volume of flights, still carries a heavy human toll. Not every incident on the official list meets a threshold of notoriety, but together they paint a portrait of an aircraft family that has been in the air long enough to encounter virtually every category of failure, from mechanical malfunction to human error to external threats. The 737's story is, in many ways, a story of aviation's broader maturation.
First Flights and First Failures
The 737's earliest years in service were marked by incidents that tested the type's operational limits. Just one day later, a 737-100 collided with a small Piper Cherokee on approach to Reus Airport in Spain; the 737 landed safely, but all three people in the Piper perished. Pilot error sent the aircraft into the ground, killing 43 of the 61 people aboard and two more on the ground. The early 1970s also saw a 737-200 strike power lines on approach to New Delhi, killing 48, and a Western Airlines jet overshoot a snow-covered runway in Casper, Wyoming, destroying the airframe. These formative incidents established patterns—crew error, environmental conditions, and the challenges of a new type finding its footing—that would echo through later decades.
Hijackings and Hostage Crises
Hijackings represent a particularly grim and recurring chapter in the 737's accident history. When the aircraft was stormed in San Francisco, both hijackers and one passenger lost their lives. Four years later, in October 1977, four Palestinians hijacked a Lufthansa 737-230C named Landshut, demanding the release of seven Red Army Faction prisoners and fifteen million dollars. The captain was fatally shot during the ordeal, and on October 17, West Germany's GSG-9 unit stormed the aircraft, killing three of the four hijackers. That same year, a Malaysian Airline System 737-200 crashed into a swamp in Johor after both pilots were shot during a hijacking attempt; the aircraft entered a phugoid oscillation and dove, killing all 100 aboard. No one was injured.
The Deadliest Moments
Several 737 accidents stand out for the sheer scale of loss of life. Pacific Western Airlines Flight 314, a 737-200, crashed on approach to Cranbrook Airport in British Columbia on February 11, 1978, after thrust reversers failed to fully stow following a go-around executed to avoid a snowplow on the runway. Forty-two of the 48 people aboard perished. These events, spanning different decades and different variants, underscore that the 737's accident record is not confined to one era or one cause.
Common Misconceptions (Editorial)
- Some may think the 737 was a direct derivative or modification of the Boeing 727. In fact, while it reused about 60% of the 727's parts and systems, it was a new design, not a derivative. - It is a common error that the 737 was built to replace or succeed the 727. Actually, it was developed to complement the 727 on shorter routes where the 727 was less economical.
Why It Matters (Editorial)
For over five decades, the Boeing 737 has been the workhorse of global aviation, enduring through four generations of design and becoming the most-produced jetliner in history. Its resilience—despite setbacks like the MAX groundings—reflects both the difficulty of innovating in aerospace and the essential role affordable, reliable narrow-body aircraft play in connecting the world.
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Frequently Asked Questions
What is the Boeing 737?
The Boeing 737 is a twin-engine narrow-body jetliner manufactured by Boeing in Washington state, conceived in the mid-1960s as a shorter, cheaper alternative to the 727 for regional routes. It kept the classic 707-series fuselage width with six-abreast seating while replacing the trijet layout with two underwing turbofans.
What are the four generations of the 737 family?
The line-up grew through the Original (-100/-200), Classic (-300/-400/-500), Next Generation (-600/-700/-800/-900), and MAX (-7/-8/-9/-10) series. Each generation swapped in newer engines, avionics, and wing technology while preserving the core 707-derived tube.
Who was the launch customer and when did the 737 enter service?
The 737-100 completed its maiden flight on April 9, 1967, and Lufthansa became the first airline to operate it in revenue service the following February. The concept had been sketched as early as 1964 to give carriers a more economical option on shorter sectors where the 727 was over-capacity.
Why did the 737 become the best-selling airliner ever?
Its low, narrow fuselage kept gate, runway, and crew costs modest, making it highly profitable on high-frequency short-haul routes where bigger jets struggled to fill seats. Boeing's strategy of refreshing the same airframe through four successive generations let operators upgrade incrementally rather than replace fleets wholesale, locking in decades of repeat orders.
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