World War I was the first war in which aircraft were deployed on a large scale. Tethered observation balloons had already been employed in several wars, and would be used extensively for artillery spotting. Germany employed Zeppelins for reconnaissance over the North Sea and strategic bombing raids over England.
Aeroplanes were just coming into military use at the outset of the war. Initially, they were used mostly for reconnaissance. Pilots and engineers learned from experience, leading to the development of many specialized types, including fighters, bombers, and ground-attack aeroplanes.
Ace fighter pilots were portrayed as modern knights, and many became popular heroes. The war also saw the appointment of high-ranking officers to direct the belligerent nations' air war effort. While the impact of aircraft on the course of war was limited, many of the lessons learned would be applied in future wars.