The 737's design advantages, such as placing the engines under the wing, a wider cabin, and versatility for cargo use, have contributed to its long-term success and appeal to airlines and low-cost carriers.

The Boeing 737 is often cited as the world's most popular commercial aircraft due to its incredible versatility, reliability, and long-standing production history that dates back to the late 1960s. One of the primary reasons for its dominance is its design as a "short-to-medium range" narrow-body jet, which fits the most common flight profiles for airlines globally. Its low-to-the-ground profile allows for easier boarding and baggage loading at smaller airports that lack sophisticated ground equipment, making it a favorite for low-cost carriers like Southwest and Ryanair. Furthermore, Boeing has evolved the 737 through four distinct generations (Original, Classic, Next Generation, and MAX), allowing airlines to upgrade their fleets while maintaining a high degree of pilot commonality and standardized maintenance procedures. This reduces training costs and spare parts inventory. With over 11,000 units delivered and thousands more on order, its massive scale ensures that almost every major airport in the world has the infrastructure and technicians ready to service a 737, cementing its status as the "backbone" of global aviation.