 Complete the following phrase:  Air warfare during World War II in Yugoslavia pitted the Yugoslav Air Force, both Royal and NOVJ, United States Army Air Force USAAF, the Royal Air Force RAF, including the Balkan Air Force, and Soviet Air Forces against the German Luftwaffe, the Italian Regia Aeronautica and the Air Force of the Independent State of Croatia Zrakoplovstvo Nezavisne Države Hrvatske, ZNDH. The latter provided the majority of the support for the ground operations against the Partisans. The Allied forces engaged in an extensive 