The Me 262 was a major improvement over other aircraft of World War II.  This German jet was 120 mph faster than the P-51, the previous  "worldbeater," and carried a powerful armament package of four 30-mm cannons.  Although the Germans did not develop an effective bombsight, the Me 262 discharged its bombs with a great deal of success.   Despite this, the Me 262 was not a major factor in the air war over Europe.  It was built in a production run of 1,433 aircraft, but only about 300 ever entered combat.