The Serbian armed forces fought in two distinct phases during the Great War. Firstly from the outbreak of the war until November 1915 the Serbians fought against the Austro-Hungarian forces invading Serbia. Secondly, after Serbia had fallen, the Serbian forces regrouped and fought on the Macedonian (Salonica) Front against German/Bulgarian/Austro-Hungarian forces from early 1916 until the end of the war.
The following chart indicates when a certain type was in use, based on various sources. It does not show how many of each aircraft was in service at any one time, but it is hoped that it will be useful in planning historically plausible scenarios. The pie chart shows the percentages of aircraft of different types in front line service at the end of the war.