With the arrival of the fleet carriers the primary striking power of the navy was no longer in its battleship force, but with the aircraft that could be brought to battle by the carriers. The means by which the US Navy operated these carriers was developed principally by Admiral Marc Mitscher. Mitscher determined that the best defense for a carrier was its own air groups, and that carriers were more easily defended if they operated together in groups, with supporting ships along with them to aid in air defense, anti-submarine defense, and rescue of downed airmen.
Said Mitscher: "The ideal composition of a fast-carrier task force is four carriers, six to eight support vessels and not less than 18 destroyers, preferably 24. More than four carriers in a task group cannot be advantageously used due to the amount of air room required. Less than four carriers requires an uneconomical use of support ships and screening vessels."
The ships of each task group sailed in a circle formation centered on the carriers. The supporting ships sailed relatively close by, and added their anti-aircraft fire to that of the carriers to help ward off attacking aircraft. When under attack by torpedo aircraft, the task group would turn toward the oncoming aircraft to limit attack angles. Other than this measure, the carriers in the task group would not take evasive action from their attackers. This was in marked contrast with the Imperial Japanese Navy, but the choice made for more stable platforms for the anti-aircraft fire of all the ships in the task group and allowed the ships in the group to sail more closely together. The primary defense of the group against air attack was the group's own fighter cover.
The individual primarily responsible for the development and operations of the task force was Admiral Marc Mitscher. The overall command of the task force alternated between two very different admirals: Raymond Spruance and William "Bull" Halsey. Halsey was aggressive and a risk taker. Spruance was calculating and cautious. Most higher-ranking officers preferred to serve under Spruance; most common sailors were proud to serve under Halsey. Their commander was Admiral Chester Nimitz.
When the force was part of Admiral Spruance's Fifth Fleet, the carrier task force was commanded by Mitscher and bore the designation Task Force (TF) 58. When led by Admiral William Halsey as part of the Third Fleet, the carrier force was commanded by Vice Admiral John S. McCain, Sr. and its designation was Task Force (TF) 38. Planning for upcoming operations was completed when each admiral and his staff rotated out of active command. This allowed the Navy to perform at a higher operational tempo, while giving the Japanese the general impression of naval assets greater than what were actually available.