Like lethal insects undergoing a series of metamorphoses into ever more mature and dangerous forms, military aircraft moved rapidly from stage to stage of their development as the 20th century progressed. The catalyst of war provided the swiftest impetus to this evolution. The new mechanized armies existing from the later period of World War I onward seized on the fresh technology and sought to squeeze every possible drop of advantage from it that the limits of science and the era's materials would allow.
Many military thinkers and even aeronautical enthusiasts believed that blimps would remain the chief military aerial asset more or less forever. These men thought airplanes would play a secondary role at best, and might even prove a uselessly expensive gimmick soon to fade back into obscurity, leaving the majestic bulk of the dirigible as sole master of the skies. Thus, when World War I began, airplane improvements occurred in an ad hoc, almost accidental manner during the war.
However, when pilots' mounting of armaments on airplanes proved a successful means of defeating other aircraft and even attacking men on the ground, a much more active and systematic development of warplanes began across the continent. Each advance prompted a countermeasure, as the two sides strove for primacy in a deadly, unforgiving environment which rewarded real advances in equipment and tactics with survival and punished poor ideas with death.
Before long, relatively powerful, heavily armed aircraft buzzed through the skies over battle-stained Europe, tearing each other apart with furious gusts of machine gun fire and sending many of the vaunted dirigibles plunging, burning, to the ground. The new era of fighting aircraft arrived in dramatic fashion.