The Boeing 737-700 is a narrow-body airliner and a variant of the 737 Next Generation series. This variant, like other 737s in the Next Generation series, features upgraded engines and overall improvements however it's fuselage is almost exactly the same of the 737-300 making it possible for it to be a like-for-like replacement for that variant from the Classic series. The 737-700 is the second shortest variant but is the second most popular variant of the Next Generations series. The 737-700, along with the it's -800 sister variant, have become the backbone of narrow-body fleets of airlines around the world. The 737-700 typically flies short to medium haul flights that have medium to high demand and has a typical seating capacity of 128 seats in a two class configuration making it a good average size plane in it's class.