<p>Spurred by the pressures of war, a technological revolution had occurred that set the style and pace for postwar aircraft and missile design and development.
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<p>The 1939 orders of battle contained biplane fighters; Great Britain, Italy and Russia still had them in front-line units, although the monoplane was fast replacing them. The primary armament for air-to-air combat was a battery of small-caliber machine guns, and the gunsight was a simple optical type, often no more refined than the bead-and-ring type used in World War I. Bombers were short-range, low-capacity monoplanes, some with a good turn of speed and able to outrun many contemporary fighters. That fact unfortunately became part of doctrine in high places and was responsible for the deaths of many bomber crewmen and the failure of many bombing missions later in the war.
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<p>By the end of the war, some fighters were powered by jet propulsion and had sweptback wings for reduced drag at their high operational speeds. Primary armament was a battery of heavy, rapid-firing cannon, or multiple mounted large-caliber machine guns. Fighters were equipped with wing strongpoints to carry such ordnance as bombs, rockets and napalm tanks. Although some air combat utilized radar sighting, most gunsights still were optical, although they had been considerably refined. The bombers had become tonnage haulers, particularly in the RAF, and were often dropping with fair precision on targets the crews never saw except as an indication on a radar scope.
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<p>Night fighting had become a rudimentary art, and German, British and US pilots and radar operators made kills under control of ground radars and their own airborne equipment for finding and sighting on the quarry.
