What change in aviation was largely due to advancements during the interwar period?

The advancements during the interwar period, particularly from World War I to World War II, significantly influenced the development of military aviation. This era witnessed rapid technological innovations that improved aircraft design, performance, and capabilities. Engineers and designers focused on enhancing speed, maneuverability, and armament, resulting in more advanced military aircraft that could perform a variety of roles—from fighters to bombers.

The interwar period also saw important developments in aerodynamics, materials, and engine technology that paved the way for highly effective and versatile military planes. Innovations such as metal construction, retractable landing gear, and variable-pitch propellers became standard, transforming the nature of aerial combat and establishing the foundation for the aircraft used in World War II.

In contrast, the other choices highlight aspects that did not characterize this transformative period in the same way. There was no disappearance of commercial airlines; instead, the commercial aviation industry began to take shape during this time. The transition to jet engines occurred after World War II, and the idea of steam-powered flight fell out of favor due to its inefficiencies compared to combustion engines. Thus, the advancements in military aircraft were the most significant change during the interwar period.