The Battle of the Philippine Sea in the Marianas in June 1944 was marked by the destruction of huge numbers of Japanese aircraft with low losses to the United States Navy. The Americans had set up an extensive program, including building a carrier that had no hangar deck, to train both aircrew and deck handlers. American pilots were entering combat with some 600 hours in the air. In contrast, the Japanese were sending green pilots into combat with only fifty hours of flight time and little combat training.
In addition, the Americans had numerical and technological superiority. The Japanese were replacing their aging B5N2 torpedo bombers with a more advanced version, the B6N Tenzan. It still lacked self-sealing fuel tanks or crew armor. In contrast, the Americans were continually introducing new aircraft. The F4F Wildcat was in service throughout the war, but after 1942 it was used as a ground attack aircraft. It was replaced in the front line carrier squadrons with the F6F Hellcat, which had more powerful armor and could dogfight with the Japanese Mitsubishi Type 00 Zero fighter. The Marines were given the F4U Corsair, which was not rated for carrier duty. Flying from forward airstrips, it was very effective against Japanese aircraft.
Nevertheless, the Japanese sent five hundred aircraft on the new carrier Taiho, the Pearl Harbor veteran Shokaku, and the hybrid carrier battleships Ise and Hyuga. They were all that was left of the First Air Fleet after three years of continuous operations. Admiral Jisaburo Ozawa’s pilots did not have night landing training, and they were given a single order — sink the enemy carriers.
On June 18, 1944, as the Americans were landing all over the Marianas, Ozawa’s search planes discovered the American Fleet. A more aggressive commander would have advanced on the Americans, but Ozawa was not Yamamoto. Cautious and slow, he chose to launch the next day when his pilots would have light to see.
The Americans were alerted to his presence by then. During the day of June 19, 1944, 429 of Ozawa’s planes were shot down for the loss of twenty-nine United States Navy planes. The one-sided engagement was the end of Japanese carrier-based air power. The Americans called the battle the ”Marianas Turkey Shoot.” Nevertheless United States Navy Admiral Raymond A. Spruance, commander of the Fifth Fleet, did not pursue the Japanese because he did not wish to leave the proximity of air cover for the land forces on the beachhead. In October, the same ships as Third Fleet under Admiral William Halsey, would abandon the landing forces to pursue Ozawa in the Battle of Leyte Gulf.
The coming fight for the Philippines would depend on the battleships of the Imperial Japanese Navy in a war that was defined by airpower. The Americans would have 1,200 aircraft on their carriers; the Japanese would have ninety. Their were few optimists left in Japan; they were reading the propaganda reports central command insisted on disseminating. Discerning officers knew their superiors were lying about the state of the war.