of Allied Macedonian Army. In the beginning of 1918 the new reorganisation was started when the 1st Squadron was formed on 17 January, and the 2nd Squadron on 1 May 1918, staffed with Serbian personnel. Serbia formed on 8 June 1915 one of the first air defense and air warning units in the world. This was due to the massive onslaught of German and Austro-Hungarian aircraft. The first airplane shot down by ground fire unit in World War I happened over skies of Serbia. During the German air attack on city of Kragujevac on 30 September 1915, air defense artillerist Radivoje-Raka Lutovac from "Tanasko Rajić" Regiment, shot his first hit, by his artillery modified gun, a Farman airplane with two crew members. Kingdom of Yugoslavia The period between two world wars was marked by a significant growth of Air Force, accompanied by the production of modern and sophisticated aircraft, with then ongoing organizational-formation changes within the Air Force. With the establishment of the Kingdom of Yugoslavia, an Army Aviation Department was formed out of Serbian and ex-Austro-Hungarian (Croatian and Slovenian) personnel. In 1923, a major initiative was launched to replace World War I era aircraft still in service with more modern designs. Contracts were placed abroad and with newly established local factories. The Aviation Department was renamed the Aviation Command and placed directly under the control of the Ministry of Military and Navy. In 1930, the Aviation Command was renamed the Royal Yugoslav Air Force (Jugoslovensko kraljevsko ratno vazduhoplovstvo). World War II The attacking forces engaged in the April War (6 to 17 April 1941) were 2,373 aircraft strong, including 1,212 aircraft from Germany, 647 from Italy and 287 from Hungary, while the Royal Yugoslav Air Force had 494 airplanes, only 269 of a modern type. Thus the ratio in the beginning of operations was 5:1 in favor of the Axis powers, and if counting only modern Yugoslav aircraft the ratio climbs to 7:1 in favor of the Axis powers. In spite of huge logistic difficulties and acts of treason (proclamation of the puppet-state Independent State of Croatia on 10 April 1941) the Royal Yugoslav Air Force fulfilled its duties with honor. Yugoslav airmen (5th and 6th Fighter Regiment pilots especially) fought courageously against an enemy superior both technically and numerically. During the war operations a total of 1,416 take-offs was made, 993 of which were performed by fighters and