Not exactly. Most of the PH sinkings were due to torpedoes, which Michell spoke against. The one BB sunk by a bomb was sunk by a 16.1" AP shell adapted into an AP bomb. Mitchell also rejected using AP bombs. All were stationary, except USS Nevada, and their AA was much less than their capability, for the first wave at least. So, as one of the commenters said, ultimately Mitchell sort of was partially correct, but for mostly wrong reasons.
Looking at battleships sunk in battle, Hiei and Kirishima absorbed a lot of bombs and torpedoes, and Hiei still had to be scuttled by IJN destroyers. Musashi and Yamato both absorbed ungodly numbers (IIRC, that was how Jonathan Parshall expressed it) of torpedoes and bombs. It would be beyond charitable to say that Mitchell oversold the ability of aircraft to sink battleships.
