Boeing 737 enters the book of Guinness World Records as “the most-produced large commercial jet” in aviation history.
The Boeing 737 is the most successful airplane model in the wold, having sold 14,532 aircraft as of 1 January 2018 with the backlog of 4,668 aircraft, including more than 4,200 orders for the 737 MAX. The Boeing rolled out the 10,000th 737 from its assembly line on 7 March 2018 and delivered to Southwest Airlines.
The medium-range, twinjet, single-isle airliner, was developed into a family of ten passenger models with capacities from 85 to 215 passengers.
The 737 was envisioned in 1964 and the first 737-100 made its first flight in April 1967, and entered service in February 1968 with Lufthansa.
The lengthened 737-200 entered service in April 1968 and then in 1980s Boeing launched the longer 737−300, −400, and −500 variants (referred to as the Boeing 737 Classic series) featuring CFM56 turbofan engines and wing improvements.
1. 1967 – 737-100 first flight
2. 1968 – 737-200 entered service
3. 1980s – launched 737−300, −400, and −500 variants known as Classic series powered by CFM56 turbofan engines
4. 1990s – 737 Next Generation (NG), 737−600, −700, −800, and −900 variants, was introduced
5. 2017 – The 737 MAX with CFM LEAP-1B engines and improved winglets entered service.
In average, around 2,000 737 airplanes are in the air at any given time, with one B737 either takeoff and/or land somewhere every two seconds.

The first 737-100

Boeing 737-200

Boeing 737-300

Specially designed winglet

Boeing 737MAX