After World War II Mikoyan-Gurevich designed jet aircraft. In the Soviet system the airplane designs of the design offices would compete to see which was the best. When the best design had been found the design would be built by the airplane manufacturing company. Even though Mikoyan-Gurevich airplanes in World War II had not been as good as airplanes by Lavochkin or Yakovlev. Mikoyan-Gurevich jet aircraft won more of the competitions to be sent to the zavods and in the time of the Cold War Mikoyan-Gurevich, together with another design office called Sukhoi, became one of the two most important design offices of fighter planes in the Soviet Union.