The Aircraft That Built Today's Southwest Airlines Is Being Retired By 2031

Southwest Airlines is the world's largest customer for the Boeing 737, having operated the type since its first flight in 1971. Apart from a brief stint flying leased 727s, the 737 has always been the sole aircraft type in Southwest's fleet. However, the airline has traditionally favored the smaller 737 variants, flying the 737-200 (admittedly, the only variant delivered in the 1970s), followed by the 737-300 and 737-500, but not the larger 737-400. Meanwhile, following the release of the 737NG family, Southwest began receiving 737-700s and simply didn't stop.