Moraitinis was born in 1891 on the island of Aegina. He entered the Hellenic Naval Academy in 1906 and graduated in 1910, joining the Navy with the rank of ensign. During the First Balkan War, Moraitinis volunteered to join the newly established Hellenic Naval Air Service which was formed at Moudros, Lemnos. On Army Lieutenant Michael Moutoussis, with Moraitinis as his observer, were ordered to observe the position of the Ottoman fleet in the Dardanelles with their hydroplane, a converted Maurice Farman MF.7. When they reached the Naranaval base they noted down the Turkish ships and installations. Additionally, Moraitinis dropped four bombs, three falling into the sea and one on the ground near a hospital, but without inflicting any serious damage or casualties. This operation is regarded as the first naval-air operation in military history and was widely commented upon in both the Greek and international press.
In 1914 Moraitinis together with Dimitrios Kamberos took the initiative and established the first naval air force academy. Moreover, the same year, he founded the first aircraft factory in Greece, a forerunner of the modern State Aircraft Factory. He was awarded British Aviator's Certificate No. 1087 on 26 February 1915; he had qualified the previous 22 September on a Sopwith seaplane at the Royal Hellenic Naval Air Station, Eleusis, Greece. When Greece joined the Triple Entente in World War I Moraitinis was transferred to the northern Aegean, where he served under the command of the British Royal Naval Air Service, piloting Sopwith Camels. On one occasion, on 20 January 1918, he 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. Moraitinis managed to shoot down three of them. For his service he was awarded with the bar to the Distinguished Service Order by the United Kingdom. By the end of the war, Moraitinis was credited with a total of nine aerial victories, making him Greece's only ace. He also became commander of the Greek Naval Air Service. On 22 December 1918, while flying from Thessaloniki to Athens, his plane crashed due to harsh weather conditions over Mount Olympus.
In addition, he received a number of citations from Greek and British commanders, and the British offered him a new Airco DH.9 with the inscription "To the Commander A. Moraitinis, D.S.O.".
