Question: Peter Isaacson served in a branch of the military in World War II that was originally formed in what year?

full_context: Document 1: Russell Brown (author): Russell Brown is an Australian author and former school teacher. He is the author of "Desert Warriors: Australian P-40 Pilots at War in the Middle East and North Africa, 1941-1943", dealing primarily with No. 3 Squadron RAAF and No. 450 Squadron RAAF.
Document 2: Daily Mail aviation prizes: Between 1907 and 1925, the Daily Mail newspaper, initially on the initiative of its proprietor, Alfred Harmsworth, 1st Viscount Northcliffe, awarded numerous prizes for achievements in aviation. The newspaper would stipulate the amount of a prize for the first aviators to perform a particular task in aviation, or to the winner of an aviation race or event. The most famous prizes were the £1,000 for the first cross-channel flight awarded to Louis Blériot in 1909 and the £10,000 given in 1919 to Alcock and Brown for the first non-stop transatlantic flight between North America and Ireland.
Document 3: Royal Air Force: The Royal Air Force (RAF) is the United Kingdom's aerial warfare force. Formed towards the end of the First World War on 1 April 1918, it is the oldest independent air force in the world. Following victory over the Central Powers in 1918 the RAF emerged as, at the time, the largest air force in the world. Since its formation, the RAF has taken a significant role in British military history, in particular, playing a large part in the Second World War where it fought its most famous campaign, the Battle of Britain.
Document 4: Peter Piper (Royal Navy officer): Captain Aston Dalzell Piper, (19 April 1913 – 8 November 1995), known as Peter Piper, was an officer in the Royal Naval Reserve in the Second World War. He was notable for two events: he was the first reservist to command a submarine, and the first reservist officer to receive the Distinguished Service Cross in the Second World War.
Document 5: Royal New Zealand Air Force: The Royal New Zealand Air Force (RNZAF) (Maori: "Te Tauaarangi o Aotearoa", "New Zealand Warriors of the Sky"; previously "Te Hokowhitu o Kahurangi", "War Party of the Blue") is the air force component of the New Zealand Defence Force. It was formed from New Zealand elements of the British Royal Air Force, becoming an independent force in 1923, although many RNZAF aircrew continued to serve in the Royal Air Force until the end of the 1940s. The RNZAF fought in World War II, Malaysia, Korean War, Vietnam and the Gulf War plus various United Nations peacekeeping missions. From a 1945 peak of over 1,000 combat aircraft the RNZAF has shrunk to a strength of around 51 aircraft in 2016, focusing on maritime patrol and transport duties in support of the Royal New Zealand Navy and the New Zealand Army. The RNZAF's air combat capability ended in 2001 with the disbanding of the A-4 Skyhawk squadrons. The Air Force is led by an air vice-marshal who holds the appointment of Chief of Air Force.
Document 6: Aircraft Research and Development Unit RAAF: The Royal Australian Air Force's Aircraft Research and Development Unit (ARDU) plans, conducts and analyses the results of ground and flight tests of existing and new Air Force aircraft. ARDU consists of four flights located at RAAF Bases Edinburgh, Amberley, Richmond and Williamtown, staffed by qualified test pilots, flight test engineers and flight test system specialists. Up until 2016 the Squadron also conducted flight test for the Australian Army with Army personnel also working within the unit. The flight test crew are long course trained at test pilot schools including the United States Air Force Test Pilot School, the United States Naval Test Pilot School, the Empire Test Pilots' School, the École du personnel navigant d'essais et de réception and the National Test Pilot School.
Document 7: List of Royal Australian Air Force air marshals: The following is a list of Australians who have attained air marshal rank within the Royal Australian Air Force (RAAF); that is, service personnel who have held the rank of air chief marshal (four-star rank), air marshal (three-star rank) or air vice marshal (two-star rank). The Royal Australian Air Force was established in 1921 as a separate branch of the Australian military forces. The service was modelled after the Royal Air Force—formed three years earlier—and adopted the same ranking system. Richard Williams, regarded as the "father" of the Royal Australian Air Force, was the service's first member to obtain air-officer rank on being promoted to air commodore (one-star rank) in 1927; he went on to become the first air vice marshal (1935) and air marshal (1940). In 1965, Sir Frederick Scherger became the first officer to be advanced to air chief marshal, one of only four members of the Royal Australian Air Force to obtain this rank as of June 2014. A further nineteen individuals have reached air marshal in the RAAF and 126 air vice marshal; seven officers have retired with the honorary rank of air vice marshal.
Document 8: Peter Holder: Peter John Holder (born 11 October 1964) is an Australian magazine publisher, journalist and non-fiction writer. In January 2013, Bauer Media Group appointed him as publisher of its joint venture titles with Hearst Magazines International. The group's magazines include Harper's Bazaar and Elle.
Document 9: Douglas Bader: Group Captain Sir Douglas Robert Steuart Bader, ( ; 21 February 1910 – 5 September 1982) was a Royal Air Force flying ace during the Second World War. He was credited with 22 aerial victories, four shared victories, six probables, one shared probable and 11 enemy aircraft damaged.
Document 10: Indian Air Force: The Indian Air Force (IAF; : "Bhāratīya Vāyu Senā") is the air arm of the Indian armed forces. Its complement of personnel and aircraft assets ranks fourth amongst the airforces of the world. Its primary mission is to secure Indian airspace and to conduct aerial warfare during armed conflict. It was officially established on 8 October 1932 as an auxiliary air force of the British Empire which honored India's aviation service during World War II with the prefix "Royal". After India gained independence from the United Kingdom in 1947, the name Royal Indian Air Force was kept and served in the name of Dominion of India. With the government's transition to a Republic in 1950, the prefix "Royal" was removed after only three years.
Document 11: Christopher Magee (fighter pilot): Christopher Lyman Magee (1917–1995) was a United States Marine Corps aviator who became a fighter ace in World War II and was one of the more colorful members of the famous "Black Sheep" squadron, VMF-214. Known as a fearless and aggressive pilot he was credited with nine victories during the war and for his heroic actions in September and October 1943 during the Solomon Islands campaign he was awarded the Navy Cross. After the war, he dabbled in bootlegging, went to Israel and flew with the Haganah during the 1948 Arab–Israeli War and later served 8 years in federal prison for bank robberies in the Chicago area. Upon his return from prison, he lived quietly on the North Side of Chicago working as a columnist and reporter for a community newspaper. He died of surgical complications while having stomach cancer tumors removed on December 27, 1995.
Document 12: Royal Australian Air Force: The Royal Australian Air Force (RAAF), formed March 1921, is the aerial warfare branch of the Australian Defence Force. It directly continues the traditions of the Australian Flying Corps (AFC), formed on 22 October 1912. The RAAF provides support across a spectrum of operations such as air superiority, precision strikes, intelligence, surveillance and reconnaissance, air mobility, and humanitarian support.
Document 13: Peter Padfield: Peter L. N. Padfield (born 1932) is a British author, biographer, historian, and journalist who specializes in naval history and in the Second World War period. His early journalism appeared under the name P. L. N. Padfield. As well as his non-fiction work, he has also published four novels.
Document 14: Peter Isaacson: Peter Stuart Isaacson, AM, DFC, AFC, DFM (31 July 1920 – 7 April 2017) was an Australian publisher and decorated military pilot. He was the owner of Peter Isaacson Publications, publisher of various trade journals and suburban newspapers including the "Southern Cross" and the "Sunday Observer" in Melbourne. During World War II, he served in the Royal Australian Air Force (RAAF) as a pilot with RAF Bomber Command and was awarded the Distinguished Flying Cross, the Air Force Cross and the Distinguished Flying Medal.
Document 15: United States Air Force: The United States Air Force (USAF) is the aerial and space warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the U.S. Armed Forces on 18 September 1947 under the National Security Act of 1947. It is the most recent branch of the U.S. Armed Forces to be formed. The USAF is the largest and one of the most technologically advanced air forces in the world. The service articulates its core functions as Nuclear Deterrence Operations, Air Superiority, Space Superiority, Cyberspace Superiority, Command and Control, Global Integrated ISR, Global Precision Attack, Special Operations, Rapid Global Mobility, Personnel Recovery, Agile Combat Support, and Building Partnerships.
ground_truth: 1921