In 1940, Greece's Air Ministry administered the Royal Greek Air Force ( Vassiliki Aeroporia
). The navy controlled the naval cooperation squadrons, and the army controlled fighters, bombers, and ground-support squadrons. The Greek air force's modern aircraft were grouped into four fighter squadrons and three bomber squadrons. At the start of the war with Italy in October 1940, Greece deployed 216 first- and second-line aircraft of all types, including liaison. Greece also had about 60 obsolete aircraft dating back to World War I. At the beginning of its invasion of Greece, Italy operated 187 modern aircraft from Albania, and it could also draw on hundreds of aircraft operating from Italy. The Greek air force was composed of a mélange of Czech, Polish, German, French, and later British machines. Greece had no reserves and was totally dependent on the British for resupply. Securing replacement parts was a nightmare, and the lack of parts meant that many aircraft became inoperable.
During 1940 and 1941, the Greek air force aggressively operated with some success in support of army operations on the Albanian Front. However, as the army advanced into mountainous Albania, flying distances became longer and more problematic, whereas Italian aircraft were able to operate closer to their own bases. By the time Germany invaded Greece in April 1941, the Greek air force was down to 41 operational aircraft. Following the Axis victory at the end of April, the Greek government in exile maintained an air force of two fighter squadrons and one bomber squadron in the Mediterranean under British control.
Arena, Nino. La Regia Aeronautica, 1939–1943. Vols. 1–4. Rome: Uffico Storico, 1982–1986.; Shores, Christopher, et al. Air War for Yugoslavia, Greece and Crete, 1940–41. Carrollton, TX: Squadron Signal Publications, 1987.