If you’re trying to be intellectually honest, you almost have to answer with “it depends on the yardstick.” Raw victory totals are the easiest metric, but they’re also the most distorted by context (front, sortie rates, target-rich environments, quality of opposition, confirmation methods).
Under the “most aerial victories” metric, Erich Hartmann is the obvious headline (352). But historians usually add caveats: the Eastern Front produced extreme engagement frequency; the Luftwaffe’s confirmation system differed from USAAF/RAF; and the nature of air combat there was often interception of massed formations at lower relative altitude with less radar control than later wars.
Under “best documented performance against elite opposition in a comparatively constrained environment,” many point to pilots like James “Johnnie” Johnson (RAF), who fought over Western Europe where survival, rotation policies, and opposition quality make high scores harder. For the US side, Richard Bong and Tommy McGuire in the Pacific are major contenders, but again: theater differences matter.
If I had to pick a single “greatest” based on a blend of skill, adaptability, leadership, and historical impact rather than totals, I’d argue for someone like Adolf Galland: not the top scorer, but a superb combat pilot, tactician, and leader who influenced doctrine and employment. It’s similar to ancient warfare: the “greatest swordsman” isn’t always the guy with the biggest pile of helmets—sometimes it’s the commander who changes how the war is fought.