World War II featured fighter combat on a larger scale than any other conflict to date. German Field Marshal Erwin Rommel noted the effect of airpower: "Anyone who has to fight, even with the most modern weapons, against an enemy in complete command of the air, fights like a savage against modern European troops, under the same handicaps and with the same chances of success." Throughout the war, fighters performed their conventional role in establishing air superiority through combat with other fighters and through bomber interception, and also often performed roles such as tactical air support and reconnaissance.
Fighter design varied widely among combatants. The Japanese and Italians favored lightly armed and armored but highly maneuverable designs such as the Japanese Nakajima Ki-27, Nakajima Ki-43 and Mitsubishi A6M Zero and Italy's Fiat G.50 and Macchi MC.200. In contrast, designers in Great Britain, Germany, the Soviet Union, and the United States believed that the increased speed of fighter aircraft would create g-forces unbearable to pilots who attempted maneuvering dogfights typical of the First World War, and their fighters were instead optimized for speed and firepower. In practice, while light, highly maneuverable aircraft did possess some advantages in fighter-versus-fighter combat, those could usually be overcome by sound tactical doctrine, and the design approach of the Italians and Japanese made their fighters ill-suited as interceptors or attack aircraft.During the invasion of Poland and the Battle of France, Luftwaffe fighters—primarily the Messerschmitt Bf 109—held air superiority, and the Luftwaffe played a major role in German victories in these campaigns. During the Battle of Britain, however, British Hurricanes and Spitfires proved roughly equal to Luftwaffe fighters. Additionally Britain's use of radar and the advantages of fighting above Britain's home territory allowed the RAF to deny Germany air superiority, saving Britain from possible German invasion and dealing the Axis a major defeat early in the Second World War.On the Eastern Front, Soviet fighter forces were overwhelmed during the opening phases of Operation Barbarossa. This was a result of the tactical surprise at the outset of the campaign, the leadership vacuum within the Soviet military left by the Great Purge, and the general inferiority of Soviet designs at the time, such as the obsolescent I-15 biplane and the I-16. More modern Soviet designs, including the MiG-3, LaGG-3 and Yak-1, had not yet arrived in numbers and in any case were still inferior to the Messerschmitt Bf 109. As a result, during the early months of these campaigns, Axis air forces destroyed large numbers of Red Air Force aircraft on the ground and in one-sided dogfights.
In the later stages on the Eastern Front, Soviet training and leadership improved, as did their equipment. Late-war Soviet designs such as the Yakovlev Yak-3 and Lavochkin La-7 had performance comparable to the German Bf-109 and Focke-Wulf Fw 190. Also, significant numbers of British, and later U.S., fighter aircraft were supplied to aid the Soviet war effort as part of Lend-Lease, with the Bell P-39 Airacobra proving particularly effective in the lower-altitude combat typical of the Eastern Front. The Soviets were also helped indirectly by the American and British bombing campaigns, which forced the Luftwaffe to shift many of its fighters away from the Eastern Front in defense against these raids. The Soviets increasingly were able to challenge the Luftwaffe, and while the Luftwaffe maintained a qualitative edge over the Red Air Force for much of the war, the increasing numbers and efficacy of the Soviet Air Force were critical to the Red Army's efforts at turning back and eventually annihilating the Wehrmacht.
Meanwhile, air combat on the Western Front had a much different character. Much of this combat was centered around the strategic bombing campaigns of the RAF and the USAAF. Axis fighter aircraft focused on defending against Allied bombers while Allied fighters' main role was as bomber escorts. The RAF raided German cities at night, and both sides developed radar-equipped night fighters for these battles. The Americans, in contrast, flew daylight bombing raids into Germany. Unescorted Consolidated B-24 Liberators and Boeing B-17 Flying Fortress bombers, however, proved unable to fend off German interceptors (primarily Bf-109s and FW-190s). With the later arrival of long range fighters, particularly the North American P-51 Mustang, American fighters were able to escort daylight raids far into Germany and establish control of the skies over Western Europe.