Air warfare on the Yugoslav Front A unique aspect of warfare on the Yugoslav Front of World War II , was the Air warfare . Air power was used in support of the ground campaigns by the Axis forces against the Partisans , with the Air Force of the Independent State of Croatia ( " Zrakoplovstvo Nezavisne Države Hrvatske " ZNDH ) , providing the majority of the support . Operations . The ZNDH flew many missions in support of Army troops in limited scale operations against the Partisans mostly over eastern and western Bosnia , as well as over Croatia using biplane Breguet 19 and Potez 25 aircraft . By September 1941 , the ZNDH introduced larger aircraft for bombing Partisan forces and territory . Visual reconnaissance missions using hand - held cameras were also flown . Aerial reconnaissance supplied the Croatian Army with vital data about Partisan movements and positions and about the situation in Partisan territory in general . This was all the more important because the Croatian Army desperately lacked radio equipment of all kinds . Light aircraft were frequently used for liaison duties , particularly connecting the surrounding NDH garrisons and higher command . Often the Army requested one or two aircraft to be temporarily attached to particular Army units to closely co - operate with ground troops . In 1942 the ZNDH participated in a large German offensive against the Partisan forces in eastern Bosnia . Initially , the Regia Aeronautica also participated in this campaign , but after a tragic incident where an Italian bomber mistakenly attacked German positions near Vlasenica , the German command assigned the ZNDH the responsibility for providing the entire aerial support mission for formations on the ground . At this time there were no significant Luftwaffe forces based in Yugoslavia . Aside from constant bombing sorties , Potez 25 and Breguet 19 aircraft were also used for daily supply missions to the besieged Croatian Army garrison at Rogatica . They would land under fire at a small improvised grass landing strip , unloading ammunition and other supplies while keeping their engines running and taking off as soon as was possible . Most of the missions were performed by the 2nd and 3rd Group ' s squadrons based at Sarajevo , which was the strongest operational base at that time . The Zagreb air base was principally employed in attacking Partisan positions in western Slavonia and Bosnia . Not only did this medium bomber force fly reconnaissance and bombing missions against Partisan forces , but also flew deep into territory under Partisan control and attacked railway stations , road traffic , agricultural depots and food stocks . The Yugoslav Partisan forces were aware of the threat to their operations that the ZNDH provided and were constantly trying to improve their anti - aircraft defence , which relied mainly on machine gun s . December 1942 also saw the return of the Croatian Air Force Legion ( HZL ) bomber squadron to Croatia from service on the Eastern Front . Upon its return the Legion ' s bomber squadron was redesignated " 1 . / ( Kroat . ) KG " after having flown its 9 Dornier Do 17Z bombers from Russia back to Croatia . The Dorniers proved a welcome addition to the strike power of the Axis forces fighting the Yugoslav Partisans on the Yugoslav Front right up to the end of 1944 . On 20 January 1943 , the German HQ in Yugoslavia launched an offensive codenamed " Fall Weiss " ( Case White ) , intending to regain the lost territory . The attack was supported by aircraft from the Luftwaffe , Regia Aeronautica and the ZNDH . Aircraft from the 2nd and 3rd Groups from Sarajevo and the 6th Group from Banja Luka were involved in bombing raids as well as leaflet dropping missions . By mid - 1943 , following the capture of southern Italy , Allied aircraft started to appear over the Balkans . NDH military command was aware of this danger and was trying to persuade the Germans to provide at least two squadrons of Messerschmitt 109 fighters to the ZNDH . However , instead of Messerschmitts , the only reinforcement fighters that came from Germany were the first of a batch of 36 overhauled captured French Morane - Saulnier M . S . 406 fighters in October , plus another dozen which arrived in December . The Germans also supplied 25 Beneš - Mráz Beta - Minor sporting two seater monoplanes , which were dispatched between the squadrons for liaison duty , as the lack of radio communications equipment at squadron level was still evident . Attacks on Yugoslav Partisan forces continued however , and on 3 October 1943 seven ZNDH Dornier Do - 17 Zs caught " 2 . bataljon " of " Brigada Braća Radić " ( 2nd battalion of the Radić Brothers Brigade ) on the move at Šemovac , on the Varaždin - Ludbreg road . In over one hour ' s concentrated aerial bombardment , the battalion sustained some sixty casualties , including 42 dead . Allied aircraft specifically started targeting ZNDH and Luftwaffe bases and aircraft for the first time as a result of the Seventh anti - Partisan Offensive , including " Operation Rösselsprung " in late May 1944 . Up until then Axis aircraft could fly inland almost at will as long as they remained at low altitude . Yugoslav Partisan units on the ground frequently complained about enemy aircraft attacking them while hundreds of Allied aircraft flew above at higher altitude . This changed during " Rösselsprung " as Allied fighter - bombers went low en - masse for the first time , establishing full aerial superiority . Consequently , both the ZNDH and Luftwaffe were forced to limit their operations in clear weather to early morning and late afternoon hours . The Allied Balkan Air Force ( BAF ) was based at Bari in Italy , and activated on 7 June 1944 and mainly supported the operations of the Partisans , led by Josip Broz Tito , against German and Independent State of Croatia ( NDH ) forces in Yugoslavia . It transported supplies to the partisans , evacuated wounded , dropped agents to help them , and provided air support in their operations against German and NDH troops . In this it was decisive in enabling the Partisans to withstand the Raid on Drvar ( Seventh Offensive ) . The Balkan Air Force was a multinational unit , with 15 types of aircraft and men from eight nations : Greece , Co - belligerent Italy , Poland , South Africa , Yugoslavia ( two squadrons of fighters ) , the UK , USA and USSR ( a transport squadron ) . Between its inception and May 1945 the BAF flew 38 , 340 sorties , dropped 6 , 650 tons of bombs , delivered 16 , 440 tons of supplies and flew 2 , 500 individuals into Yugoslavia and 19 , 000 ( mostly wounded ) out . The Dornier Do 17 medium bombers of the ZNDH were still hitting back when and where they could and on 31 December 1944 a Dornier Do - 17E attacked an RAF 148 Squadron Handley Page Halifax bomber on the ground at the Partisan airfield at Grabovnica near Čazma , destroying it with bombs . On 10 February 1945 , a single ZNDH Dornier Do 17Z caught " 1 . Zagorska Brigada " ( 1st Zagorje Brigade ) marching in the open near Daruvar . The Yugoslav Partisan unit suffered some two dozen casualties . On 15 April 1945 , a force made up of a Dornier Do - 17Z , escorted by two Messerschmitt 109G s destroyed two aircraft of the Yugoslav Partisans at their airfield at Sanski Most . Towards the end of its existence , the BAF operated a small number of units from Yugoslav soil to harass the retreating Germans . However , disagreements with Tito ( particularly the arrest of members of the Special Boat Squadron on 13 April 1945 , although they were quickly released ) meant that all British ground forces were withdrawn , although BAF aircraft operating from Zadar continued to support the Partisan offensive . Between 19 March and 3 May they flew 2 , 727 sorties , attacking the German withdrawal route from Sarajevo to Zagreb and supporting the Fourth Yugoslav Army advancing from Bihać to Fiume ( Rijeka ) .