How long is the Boeing 737?

The original 737 from the 1960s measured just over 28 meters, but Boeing has stretched the fuselage with each generation to gain capacity without designing a whole new aircraft. The current generation, the 737 MAX, keeps that approach: the MAX 7 measures about 35.6 meters, the MAX 8 — the best seller — 39.5 meters, the MAX 9 is around 42.2 meters, and the MAX 10, the longest of the whole family, reaches 43.8 meters from nose to tail. Each stretch adds rows of seats without touching the wings, engines or systems, which keeps development costs down compared with an entirely new aircraft.

Stretching the fuselage isn't free: beyond a certain point, the rear of the aircraft can strike the runway when rotating on takeoff if the landing gear isn't adapted, and evacuation rules require that all passengers be able to exit within 90 seconds with half the exits blocked. The 737 MAX 10 needs a slightly longer landing gear precisely because of that geometric issue, and its length is close to the maximum allowed under certification with the current number of exits without adding doors.

Length isn't just a technical detail: in the rivalry with the Airbus A320 family, each stretch of the 737 responds to an equivalent move by the competitor. Airbus answered the 737 MAX with the A321neo, today the longest version of its family, in a direct contest for the highest-capacity segment of the single-aisle market.