Moraitinis managed to establish the first naval aviation school and corps. In spring 1915 the establishment of an independent Naval Aviation Department within the Ministry for Naval Affairs and the incorporation of the Greek naval air fleet into the Greek Navy ensured the foundation of the Naval Air Service (NAY). Meanwhile, disagreements between King Constantine I and Prime Minister Eleftherios Venizelos over whether Greece should enter World War I, lead to political instability and the National Schism (1914–1916). Greece officially joined the Triple Entente at June 1917, however the anti-royalist party of the country under the leadership of Venizelos formed a Movement of National Defence that supported the Allied military operations in the region from December 1916. During the following years (1917–1918), a fighter and bomber squadron, known as "Z" Squadron (), was created by Greek personnel under direct Royal Naval Air Service command and carried out operations in the northern Aegean, based at Moudros (Lemnos) and Thasos. Moreover, a joint Army-Navy flight school was established at Moudros. The activity of "Z" Squadron included anti-submarine sweeps, attacks against targets of vital importance, as well as dogfights. Among the most significant missions were the night raids against the Gallipoli-Constantinople peninsula in June 1917, the heavy bombings of enemy positions in the Macedonian front, as well as Izmir, Ottoman Empire. In 1918 the Naval Aviation had four squadrons of Sopwith Camel biplanes and other aircraft, while each one counted ca. 10–12 aircraft. Aristeidis Moraitinis, the commander of the Hellenic Naval Air Service, acquired the nickname the Fearless Aviator by his British colleagues and counted nine victories in total, becoming so Greece's only World War I ace. In one occasion, on 20 January 1918, Moraitinis, fought ten enemy aircraft which attacked two British Sopwith Baby seaplanes he was escorting on their way to bomb the Turkish battlecruiser Yavuz Sultan Selim (the former German ) and managed to shoot down three of them. Greco-Turkish War and Interwar period In the following Greco-Turkish War of 1919–1922 the Naval Aviation formed one squadron, that together with additional four of the Army Aviation Service participated in operations in Asia Minor. This squadron () initially consisted of 10 Airco DH.9 bombers and 15 Sopwith Camel F.1 fighters. The Asia Minor Campaign was followed by a long period of peace during which both the Hellenic Army and Naval Aviation Services were reorganized and upgraded. From 1925 new types of