The main Japanese carrier-based aircraft were the Aichi D3A1 dive bomber and the Nakajima B5N2, which was used either as a torpedo bomber or as a bomber. However, production of the D3A had been reduced, while production of the B5N had been stopped. None were available to replace losses. In addition many of the aircraft being used during the June 1942 operations had been operating since late November 1941; many were almost worn out and had become increasingly unreliable. These factors meant that all carriers of the "Kido Butai" had fewer aircraft than normal and there were not enough spare aircraft or parts. I