en.Wedoany.com Reported - Southwest Airlines is advancing its fleet renewal plan, gradually replacing its aging 737NG series with the Boeing 737 MAX family. The airline currently operates 737-700 and 737-800 fleets with average ages of 19.8 years and 10.5 years, respectively, and maintenance costs for older aircraft are rising significantly.

Founded in 1967 as Air Southwest Co., Southwest Airlines made its first flight in 1971. Since its inception, the airline has operated exclusively Boeing 737 series aircraft, a single-fleet strategy that continues to this day. Over time, it has operated six 737 variants and served as the launch customer for three of them.

According to ch-aviation data, Southwest Airlines' most popular model is the 737-700, with 310 in operation, 24 of which are parked. The airline took delivery of its first 737-700 in December 1997, serving as the launch customer for the Boeing 737NG (Next Generation) program. By June 2018, its 737NG fleet had exceeded 500 aircraft. As aircraft age, more frequent and in-depth inspections, component replacements, and overhauls are required annually, with heavy maintenance checks costing millions of dollars each.

The Boeing 737 NG series debuted in 1997, with over 7,000 units delivered cumulatively. Compared to the Classic series, it features larger wings, higher fuel capacity, and greater range. However, compared to the NG series, newer aircraft like the 737 MAX achieve double-digit percentage reductions in fuel consumption, and the NG series lacks modern amenities such as power outlets and upgraded interiors.

Southwest Airlines is heavily investing in the 737 MAX model. According to ch-aviation data, the airline has taken delivery of 303 737 MAX 8 aircraft, with 193 more pending delivery and 259 uncertified MAX 7s. The 737 MAX 7 is designed to directly replace the 737-700, offering more seats and higher fuel efficiency. The series also features split-tip winglets and CFM International LEAP engines (each producing nearly 30,000 pounds of thrust), aimed at further improving aerodynamic performance and fuel efficiency.

By transitioning to the 737 MAX family, Southwest Airlines aims to reduce pilot training differences, simplify maintenance processes, and streamline spare parts inventory, thereby achieving lower operating costs. Currently, its 737 MAX 8 fleet has an average age of just 3.5 years. Historically, Southwest has also operated models such as the Boeing 737-200, 737-300, and 737-500, as well as 88 Boeing 717-200s acquired through the purchase of AirTran Airways (which were not integrated into its own fleet and were leased to Delta Air Lines).

The 737 MAX series entered commercial service in May 2017. Currently, only the MAX 8 and MAX 9 are certified, while Boeing is still awaiting certification for the MAX 7 and MAX 10. The series also incorporates minor aerodynamic optimizations such as a redesigned tail cone and improved APU exhaust.