http://en.wikipedia.org/wiki/Battle_of_Midway#Impact
But most importantly of all, Midway bought the United States valuable time until the new Essex-class fleet carriers became available at the end of the year.
[127] The loss of the Akagi, Kaga, Soryu and Hiryu reduced the number of operational carriers that Japan could use against the US which still had the Enterprise, Hornet, Wasp and Saratoga...
Some authors have stated heavy losses in carriers and veteran aircrews at Midway permanently weakened the Imperial Japanese Navy.[128] Parshall and Tully, however, have stated that the losses in veteran aircrew, while heavy (110, just under 25% of the aircrew embarked on the four carriers),[129] were not crippling to the Japanese naval air-corps as a whole: the Japanese navy had some 2,000 carrier-qualified aircrew at the start of the Pacific war.
[130]
A few months after Midway, the JNAF sustained similar casualty rates at both the
Battle of the Eastern Solomons and
Battle of Santa Cruz, and it was these battles, combined with the constant attrition of veterans during the Solomons campaign, which were the catalyst for the sharp downward spiral in operational capability.
[131] However, the loss of four large fleet carriers, and over 40% of the carriers' highly trained aircraft mechanics and technicians, plus the essential flight-deck crews and armorers, and the loss of organizational knowledge embodied by such highly trained crew, were heavy blows to the Japanese carrier fleet.
[131][nb 10]
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