The Boeing 737 was one of the most successful airplanes of all time. It is the most delivered commercial aircraft to date (although now overtaken in orders by the Airbus A320). The first 737-100 entered service in 1968, and the type went through several variants leading to the 737 MAX series today. The usage and operators of these variants have, of course, varied. Here we take a look at the biggest airline operators of each variant.
The Boeing 737-100 – Lufthansa
The launch of the 737-100 was a big step for Boeing. The new narrow body was developed as a successor to its 707 and 727 aircraft. The 727 had been a great success, but there was merit in following it with a more economical twin-engine aircraft. Boeing opted for a different design from the competition, with engines mounted under the wings, which of course has become standard today. This allowed for a wider aircraft cabin and easier access to ground engines.
The 737-100 entered service in February 1968, with launch customer Lufthansa. Only 30 of these original aircraft were ordered and Lufthansa was by far the largest operator – with 22 aircraft operated in total. It retired all aircraft in 1981 and 1982. Among US airlines, Continental Airlines was by far the largest operator, with 17 aircraft operated (including some ex-Lufthansa aircraft). He kept the aircraft in service until 1998.
All fleet information here is based on data from ATDB.aero.
Lufthansa was the launch customer and largest operator of the Boeing 737-100. Photo: Getty Images
The Boeing 737-200 – US Airways
The 737-200 was introduced shortly after the 737-100 and met airline demand for higher capacity (typical capacity increased from 85 to 102), and also featured more powerful engines. It continued to be a big hit for Boeing (despite slow initial sales) and set the Boeing 737 series on a path to dominance – over 1,100 aircraft were delivered with a small number still in operation.
Lufthansa was a major operator of this type in Europe – operating 45 aircraft (and six other freighter versions). But US airlines have taken the lead as the biggest operators. US Airways operated the most – with 110 737-200s including a large number from Piedmont Airlines. United Airlines is close behind, with 100 planes in total, and Delta Air Lines operated 76 planes.
The Boeing 737-300 – Southwest Airlines
The 737 Classic series was launched with the 737-300 in 1984. This kept commonalities with the previous variants but offered improvements in capacity, power and efficiency. The series was a great success for Boeing. It remained in production until 2000 and a total of 1,988 aircraft were delivered.
The 737-300 was the mid-size option, with a typical two-class capacity of 126. It was again popular with most major US airlines. Southwest Airlines, however, became the largest operator of this mid-size variant. Its introduction matched well with the airline’s growth years and it operated 196 aircraft in total. It had also operated the 737-200, with 61 aircraft in total.
The Boeing 737-400 – US Airways
The 737-400 lengthened the 737-300 by about three meters and increased capacity to 188. Southwest Airlines stuck with the midsize 737-300, letting other airlines lead the way with the 737-400. United Airlines and Delta Air Lines have also not adopted this larger variant.
The largest operator was US Airways, with 73 aircraft in its fleet. Alaska Airlines was also a notable operator – operating only the 737-400 of this series, with 40 aircraft (including freighter versions). Outside the United States, British Airways was a primary operator, with 45 aircraft (it was also one of the only major airlines to operate all three Classic Series variants).
The Boeing 737-500 – United Airlines
The 737-500 is the smallest member of the Classic series, with a typical two-class capacity of 110, making it a perfect replacement for the 737-200. United Airlines did just that and became the largest operator, with 91 planes (including those it took from Continental Airlines, also a major operator). Southwest Airlines also adopted this smaller variant, with 39 aircraft operated in total.
The Boeing 737-600 – SAS
Boeing launched the 737 Next Generation series in 1993 (the first aircraft flying in December 1997, with launch customer Southwest Airlines). The development was driven by the launch of the Airbus A320 and its more efficient operation.
The 737-600 was the smallest of the four Next Generation variants, with a typical two-class capacity of just 108. It was also the lowest-selling of the Next Generation series (and second lowest after the 737-100) , with only 69 new aircraft delivered. Southwest Airlines never operated this smaller variant. Instead, SAS has been the largest operator, with 26 planes, with the last in service until 2019.
The Boeing 737-700 – Southwest Airlines
The 737-700 is stretched by about 2.4 meters, bringing its typical capacity to 128. It was the first variant launched, entering service with Southwest Airlines in December 1997. Southwest Airlines was by far the largest operator, with an incredible 516 aircraft operated in total. As of April 2022, 426 aircraft are in active service.
The Boeing 737-800 – Ryanair
The 737-800 is more stretched than the 737-700, making it a suitable replacement for the 737-400. It can accommodate up to 189 passengers. Its compromise to offer both good range and good capacity made it the best selling of all the 737 variants.
Southwest Airlines operated 207 aircraft (all still in service). It is just beaten to first place in the United States by American Airlines, with 303 737-800 aircraft. But overall, European low-cost airline Ryanair operates the most, with 402 planes spread across the mainline and its subsidiaries. The 737-800 makes up the bulk of Ryanair’s fleet of 497 planes (plus more that have been retired), with the Boeing 737 MAX 200 starting to replace them from 2021.
Frankfurt-Hahn and Rome-Ciampino remain important bases for Ryanair today. Photo: Getty Images
The Boeing 737-900
The longest variant of the Next Generation series last entered service in 2000. Delta Air Lines narrowly edged United Airlines for the top spot with 159 aircraft (down from 148). Outside the United States, Indonesian airline Lion Air is also a major operator, with 63,737-900 aircraft.
Boeing 737 MAX Series – Southwest Airlines
The Boeing 737 MAX series was announced in 2011 (and introduced in 2017), again largely in response to developments by Airbus and the A320neo family. The 737 MAX uses CFM International’s new LEAP engines and features several aerodynamic modifications, including distinctive winglets, to significantly improve efficiency. There have clearly been delays and problems with orders and deliveries following the type’s grounding in 2019.
There are still many 737 MAX aircraft on order – 4,138 based on Boeing data as of April 2022. The current largest operators of the types already launched are (based on ch-aviation.com data):
- Boeing 737 MAX 8 – Southwest Airlines currently operates 71 aircraft and has ordered 67 more. American Airlines follows that with 42 planes in service and 81 more on order.
- Boeing 737 MAX 9 – United Airlines operates the most with 30 MAX 9 aircraft (and 36 more on order), followed by Alaska Airlines with 20 aircraft.
- Boeing 737 MAX 200 – It is only operated by Ryanair, with 64 aircraft currently in service at its subsidiaries.
Only Ryanair operates the 737 MAX 200. Photo: Ryanair
The Boeing 737 has been around for over 50 years. Feel free to discuss the different variants, their past and current orders, and who will lead the way in the future.
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