How many generations does the Boeing 737 family have?

The family starts with the Original series, the first generation, made up of the 737-100 and the 737-200. It also includes the military derivatives T-43 and CT-43. That first generation was launched in February 1965. The 737-100 entered service in February 1968. The 737-200 followed in April 1968. The second generation is the Classic series, made up of the 737-300, -400 and -500, launched in 1979. These aircraft began commercial operations in 1984. The first to do so was the 737-300, which USAir introduced on 28 November 1984.

The third generation was named the Next Generation series and comprises the 737-600, -700, -800 and -900. The military C-40 and P-8 are derived from this same generation. It was launched in late 1993. Next Generation variants entered service starting in 1997. Southwest Airlines received its 737-700 in December 1997.

The fourth generation is the 737 MAX series, with the 737-7, -8, -9 and -10, launched in August 2011. The first delivery took place on 6 May 2017, to Malindo Air. That airline began the model's commercial operations on 22 May 2017.