Early systems relied on rapid-firing guns, mechanical control computers, and sound locators. In WWII, "flak" (German: Flugabwehrkanone ) became a major combat hazard for bombers, often causing more losses than enemy fighter aircraft.
The technology and application of anti-aircraft measures have evolved significantly since World War I: antiaircraft
Contemporary systems utilize advanced radar, satellite constellations, and autonomous targeting. Anti-Aircraft Warfare Research Report 2024 - Yahoo Finance Early systems relied on rapid-firing guns