The Boeing 737 quickly became the world's best selling airliner, surpassing Boeing's own 727 who previously held that title, and also holds the record for being the longest continuously produced commercial airliner since 1967. Boeing first introduced the 737-100, which did not sell well only ever being flown by a handful of operators after entering service in 1968 with Lufthansa. The 737-200, which also entered service in 1968 with United Airlines, offered a slightly stretched fuselage and better range, was much more popular and a mega success for Boeing. A new generation of 737s with modern electronic flight instruments were introduced in the 1980s, known now as the "Classic" series, with the 737-300 being introduced by Southwest Airlines in 1984, the stretched 737-400 being introduced by Piedmont Airlines in 1988 just before their merger with USAir, and the shorter 737-500, with better range and the same seating capacity as the older 737-200, was also launched by Southwest Airlines in 1989. These aircraft were followed by the "Next Generation", or "Next Gen" 737 series which featured state-of-the-art electronics and instruments with greater range, but retained some antiquated details such as the old overhead panel of pervious versions at the request of major customers like Southwest Airlines to enable fleet commonality so pilots could fly both Next Gen and Classic types. Southwest Airlines introduced the 737-700 in 1997, while the stretched 737-800 was introduced in 1998 by Hapag-Lloyd Flug while the much shorter 737-600, meant to be a direct 737-500 replacement, was introduced by SAS that same year. As the 737-600 had very similar economics to the 737-700 but with less capacity, it was not popular and production ended with only a small number of aircraft produced, many of which were retired by their operators prematurely. The largest of the classic, the 737-900 which was envisioned as a 757 replacement in terms of capacity, but not performance, was introduced by Alaska Airlines in 2001. By the early 2000s, Boeing began retrofitting it's Next Gen series with new blended winglets, and by the 2010s, most 737s world wide had made the retrofit for reasons of fuel efficacy. Boeing later began retrofitting 737-300s and 737-500s with new, smaller winglets, but most operators retired their fleets before retrofitting them. In the early 2010s, Boeing further modified the winglets with the "Split Scimitar" winglets further reducing drag and increasing range, and many airlines across the globe have since retrofitted their aircraft. The Next Gen series was followed by the MAX series, featuring increased range and economics with new modern "LEAP" engines and new avionics while again retaining the classic overhead panel more or less for reasons of pilot commonality with the 737 Next Gens. The 737MAX8, a direct replacement for the 737-800, was introduced in 2017 by Malindo Air, while the stretched 737MAX9, a 737-900 direct replacement with much better performance, was launched by Lion Air in 2018. Sadly, the banana-like curve at the front of the fuselage was countered with a digital stall detection and prevention system called "MCAS", and issues with this feature resulted in 2 fatal crashes with large loss of life with Lion Air and Ethiopian Airlines both losing 737MAX8s shortly after departure. This lead to a 20-month global grounding of the type, and delayed the introduction of the 737MAX7, a direct 737-700 replacement, and the 737MAX10, a further stretched version of the 737MAX9, with neither type having yet entered passenger service. To this day, there are operating commercial examples of every 737 type except for the 737-100, with the last example having been retired by Aero Continente in 2005.

Currently, no available pilots have flown the 737-100 or 737-200, but attempts to find pilots for these types may be attempted upon request with no guarantee.

Currently, the following realistic add-ons are available for these aircraft:

PMDG 737 Next Gen: Prepar3Dv4/5, Flight Simulator X/Prepar3Dv1-3

MO Textures 737MAX: Prepar3Dv4/5 (requires PMDG 737 for cockpit, message page and request the 737MAX merge)

MAX Team Design 737MAX/Next Gen: X-Plane (Free, but cockpit lacks some features)

Threshold LevelUP 737 Next Gen: X-Plane (free, improved from the default 737)

ZEBO 737 Next Gen: X-Plane (free, improved from default 737 but very high quality)

Captain Sim 737 Classic: Prepar3Dv4/5

IXEG 737 Classic: X-Plane

FeelThere/Wilco 737 Classic: Flight Simulator X/Prepar3Dv1-3