Surviving carriers reshape the Denmark Strait battle

By this point the Mediterranean war may already have diverged so far that Cape Matapan never occurs in its historical form. The same surplus of flight decks could place Courageous or Victorious with Hood and Prince of Wales in the North Atlantic. Carrier reconnaissance could identify Bismarck and Prinz Eugen's formation before Admiral Holland committed to the gun battle. Swordfish strikes might then damage Bismarck before surface contact, giving the British commander more information and tactical options. The helicopter need not attack Bismarck itself to matter because preventing earlier carrier losses changes which conventional aircraft are present later.