Question: What branch of the service that has the world's largest aircraft carrier fleet did William D. Halyburton Jr receive the Medal of Honor from?

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List of sunken aircraft carriers: With the advent of heavier-than-air flight, the aircraft carrier has become a decisive weapon at sea.  In 1911 aircraft began to be successfully launched and landed on ships with the successful flight of a Curtiss Pusher aboard the USS "Pennsylvania".  The British Royal Navy pioneered the first aircraft carrier as floatplanes, as flying boats under performed compared to traditional land based aircraft.  The first true aircraft carrier was the HMS "Argus" , launched in late 1917 with a complement of 20 aircraft, a flight deck of 550 ft and 68 ft wide.  The last aircraft carrier sunk in wartime was the Japanese carrier "Amagi", in Kure Harbour in July 1945.  The greatest loss of life was the 2,046 killed on the "Akitsu Maru"—a converted passenger liner with a small flight deck, carrying the Imperial Japanese Army's 64th Infantry Regiment.

USS Midway (CV-41): USS "Midway" (CVB/CVA/CV-41) was an aircraft carrier of the United States Navy, the lead ship of her class.  Commissioned a week after the end of World War II, "Midway" was the largest ship in the world until 1955, as well as the first U.S. aircraft carrier too big to transit the Panama Canal.  A revolutionary hull design, based on the planned "Montana"-class battleship , gave her enhanced protection compared to previous carriers.  She operated for 47 years, during which time she saw action in the Vietnam War and served as the Persian Gulf flagship in 1991's Operation Desert Storm.  Decommissioned in 1992, she is now a museum ship at the USS "Midway" Museum, in San Diego, California, and the only remaining U.S. aircraft carrier commissioned right after World War II ended that was not an "Essex"-class aircraft carrier .

Japanese aircraft carrier Akagi: Akagi (Japanese: 赤城 "Red Castle") was an aircraft carrier built for the Imperial Japanese Navy (IJN), named after Mount Akagi in present-day Gunma Prefecture.  Though she was laid down as an "Amagi"-class battlecruiser , "Akagi" was converted to an aircraft carrier while still under construction to comply with the terms of the Washington Naval Treaty.  The ship was rebuilt from 1935 to 1938 with her original three flight decks consolidated into a single enlarged flight deck and an island superstructure.  The second Japanese aircraft carrier to enter service, and the first large or "fleet" carrier, "Akagi" figured prominently in the development of the IJN's new carrier striking force doctrine that grouped carriers together, concentrating their air power.  This doctrine enabled Japan to attain its strategic goals during the early stages of the Pacific War from December 1941 until mid-1942.

Type 002 aircraft carrier: The Type 002 aircraft carrier is a second generation Chinese aircraft carrier design.  The ship will be the first Chinese aircraft carrier to be equipped with a catapult.  According to the latest report, the construction of this carrier has been rescheduled for a decision on the catapults, where the latest competition results suggested that steam catapults will be used in the Type 002 aircraft carrier.  The addition of aircraft catapult will give China the ability to launch various fixed wing support aircraft like airborne early warning (AEW) and carrier onboard delivery aircraft.  Fighters can also be launched at full combat load and reach its full potential unlike current Type 001 aircraft carriers operated by Chinese navy.

William D. Halyburton Jr.: William David Halyburton Jr. (October 2, 1924 – May 10, 1945) was a United States Navy hospital corpsman who was killed in action during World War II while assigned to a Marine Corps rifle company.  He was posthumously awarded the nation's highest military decoration for valor, the Medal of Honor, for heroic actions "above and beyond the call of duty" on May 10, 1945, during the Battle of Okinawa.

Escort carrier: The escort carrier or escort aircraft carrier (hull classification symbol CVE), also called a "jeep carrier" or "baby flattop" in the United States Navy (USN) or "Woolworth Carrier" by the Royal Navy, was a small and slow type of aircraft carrier used by the Royal Navy, the Imperial Japanese Navy and Imperial Japanese Army Air Force, and the United States Navy in World War II.  They were typically half the length and a third the displacement of larger fleet carriers.  While they were slower, carried fewer planes and were less well armed and armored, escort carriers were cheaper and could be built quickly, which was their principal advantage.  Escort carriers could be completed in greater numbers as a stop-gap when fleet carriers were scarce.  However, the lack of protection made escort carriers particularly vulnerable and several were sunk with great loss of life.  The light carrier (hull classification symbol CVL) was a similar concept to escort carriers in most respects, but were capable of higher speeds to allow operation alongside fleet carriers.

USS Halyburton (FFG-40): USS "Halyburton" (FFG-40), an "Oliver Hazard Perry"-class frigate , is a ship of the United States Navy named for Pharmacist's Mate Second Class William D. Halyburton, Jr. (1924–1945).  Halyburton was posthumously awarded the Medal of Honor for his heroism while serving with the 5th Marines, during the Battle of Okinawa in 1945.

Light aircraft carrier: A light aircraft carrier, or light fleet carrier, is an aircraft carrier that is smaller than the standard carriers of a navy.  The precise definition of the type varies by country; light carriers typically have a complement of aircraft only one-half to two-thirds the size of a full-sized fleet carrier.  A light carrier was similar in concept to an escort carrier in most respects, however light carriers were intended for higher speeds to be deployed alongside fleet carriers, while escort carriers usually defended convoys and provided air support during amphibious operations.

List of escort carriers of the Royal Navy: The escort aircraft carrier, also called a "jeep carrier" or "baby flattop" in the USN or "Woolworth Carrier" by the RN, was a small and slow type of aircraft carrier used by the Royal Navy in the Second World War.  They were typically half the length and one-third the displacement of the larger fleet carriers.  While they were slower, less armed, unarmoured and carried fewer aircraft, they were less expensive and could be built more quickly.  This was their principal advantage, as escort carriers could be completed in greater numbers as a stop-gap when fleet carriers were scarce.  However, the lack of protection made escort carriers particularly vulnerable and several were sunk with great loss of life.  The light carrier (hull classification symbol CVL) was a similar concept to escort carriers in most respects, but they were designed for higher speeds for deployment with fleet carriers.

United States Navy: The United States Navy (USN) is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States.  The U.S. Navy is the largest, most capable navy in the world, with the highest combined battle fleet tonnage.  The U.S. Navy has the world's largest aircraft carrier fleet, with eleven in service, one in the reserve fleet, and two new carriers under construction.  The service has 322,421 personnel on active duty and 107,577 in the Navy Reserve.  It has 276 deployable combat vessels and more than 3,700 operational aircraft as of 2017 .

Supporting paragraphs: William D. Halyburton Jr. United States Navy
Answer: United States Navy