Air Force of the Independent State of Croatia The Air Force of the Independent State of Croatia ( , ZNDH ) , was the air force of the Independent State of Croatia ( NDH ) , a puppet state established with the support of the Axis Powers on the territory of the Kingdom of Yugoslavia during World War II . The ZNDH was founded under German authority in April 1941 , following the German - led Axis invasion of Yugoslavia . Although it could not be considered a large air arm in the wider context of World War II , the ZNDH nonetheless had on its charge at one time or another some 650 aircraft between April 1941 and May 1945 , as well as anti - aircraft and paratroop units . From humble beginnings in 1941 , the ZNDH was still providing some measure of air - support ( fighter , attack and transport ) until the last days of World War II in Europe . The ZNDH maintained a flying training school equipped with gliders and trainers , originally at Rajlovac airfield near Sarajevo and then at Velika Gorica and Pleso airfields in Zagreb . Its parachute and paratroop school was located in Koprivnica . History . Establishment . The ZNDH came into being as early as 19 April 1941 , just nine days after the proclamation of the NDH . It become operational almost at once . Its commander was Colonel Vladimir Kren , a former captain of the Royal Yugoslav Air Force ( lang - sh | " Vazduhoplovstvo Vojske Kraljevine Jugoslavije " , VVKJ ) , who had defected to the Germans in Graz in his Potez 25 on 4 April 1941 and declared himself an Ustaše supporter . The first task of the new air force , the backbone of which was provided by 500 former VVKJ officers and 1 , 600 NCOs , was the acquisition or salvage of aircraft , weapons , machinery , equipment and fuel that had survived the fighting and had not been confiscated by the German or Italian forces . Following the brief April War , the Germans had captured over 300 ex - VVKJ aircraft . They considered them to be of little use for the Luftwaffe , so it was decided to equip the ZNDH with an appropriate number of these aircraft . These aircraft , scattered in every corner of Yugoslavia , were then collected , minor damage repaired and stocks of fuel and spare parts stored at airfield workshops . Naturally , the majority of the aircraft were more or less damaged and action was undertaken to repair as many of them as possible . Former VVKJ pilots of Croatian background and other personnel of aeronautical specialty were approached and offered instant rehabilitation ( most of them were in German POW camps ) , jobs and safety for their families . Kren also initiated the formation of an early warning system , anti - aircraft batteries ( armed with German and Czech weapons ) and various training and servicing departments , ammunition stores and workshop facilities . The fuel necessary for the operations of the ZNDH was supplied by the Germans from former Yugoslav stocks in Kraljevo , Serbia . As early as May 1941 , the NDH had asked Germany for , among other things , 22 Messerschmitt 109 s . Instead , they got some of the remaining largely obsolete aircraft of the VVKJ . At the same time , Germany appropriated six captured Dornier Do 17K bombers , which were then supplied to Bulgaria . Romania received six ex - VVKJ Hawker Hurricane s , as well as six Bristol Blenheim s , whilst Finland received 20 half - completed Blenheims , together with manufacturing tools and production equipment , as well as a huge variety of spare parts . During the middle part of 1941 , some of the ZNDH ' s man - power capacity ( one fighter squadron and one medium bomber squadron ) was sent to the Eastern Front as part of the Luftwaffe , the Croatian Air Force Legion ( , HZL ; ) . Most of the Croatian Air Force Legion ' s personnel were back on NDH territory by late 1942 ( bomber squadron ) / early 1944 ( fighter squadron ) to help counter the growing Allied air threat . The personnel of the ZNDH took over and re - activated the airfields at Zagreb , Sarajevo , Mostar , Banja Luka and Zemun , where the Ikarus and Zmaj aircraft plants were located . By June 1941 , the Germans had begun to pass on to the ZNDH various captured VVKJ aircraft , including eight Bristol Blenheim I and five Potez 25 bombers . These and most of the 211 ex - VVKJ aircraft received by the ZNDH had first to be repaired and / or overhauled at the Ikarus plant in Zemun . The first missions : 1941 . In late 1941 the ZNDH had 95 aircraft distributed in four groups and eight squadrons . Fighting the Yugoslav Partisans from the air had begun already in late June 1941 , when Breguet 19 and Potez 25 bombers had proved most suitable . The Breguets could carry a bomb load of up to using 24 bombs , whilst the Potez 25s could carry about half that amount . Both types were also armed with three machine gun s . Altogether the ZNDH eventually came to possess 50 Breguet 19s and 45 Potez 25s . The operational use of these light bombers was not limited to fighting the Partisans ; the aircraft were also used to supply isolated or surrounded army strong points . The emblem of the ZNDH was to be the red and white chequerboard insignia , ( ) , derived from the Croat coat of arms , dating back to the 10th century , carried on the fin . In January 1945 this was replaced by the black and white trefoil cross of King Zvonimir . As well as the Breguet and Potez aircraft , which were the most numerous types in the ZNDH inventory , Zmaj Fizir FP - 2 light biplane trainers were also converted to carry six bombs . These aircraft were used to bomb and strafe Partisan troops and positions in northern Bosnia but they also faced anti - aircraft fire . The first missions cost the ZNDH a Breguet and a Potez aircraft , both of which crash landed after being hit by Partisan ground fire . The ZNDH crews had little chance of survival after being hit , as flying suits , helmets and parachutes were not available at the time - hence their desperate crash - landings . Similar actions continued throughout 1941 . 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 other parts of the NDH . By September , the ZNDH introduced larger aircraft for bombing Partisan forces and territory . Two bombers , an Avia Fokker F . IX derived F . 39 and a Savoia - Marchetti SM . 79 were available for operations and had the added advantage of being able to carry bombs . They were extensively used for bombing villages and road communications . However it was soon established that the vintage biplane Breguet 19 and Potez 25 aircraft were ideally suited for missions against Partisan troop concentrations . Although they were outdated and certainly their use would be out of the question on any other front , their performance and armament made them very dangerous for an ill - armed enemy . The Partisans were scattered in villages , forests and mountains and their positions could only be detected by a slow moving aircraft . Visual reconnaissance missions using hand - held cameras were also flown . Aerial reconnaissance supplied the 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 army desperately lacked radio equipment of all kinds . Light aircraft were frequently used for liaison duties , particularly connecting the surrounding army 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 . The ZNDH ' s fighter force was poorly equipped in every respect , consisting of 12 ex - VVKJ machines including four Ikarus IK - 2 s , seven ancient Avia BH - 33 E s and one Hawker Fury II . Fortunately for this ill - equipped force , there was no aerial opposition and some more modern fighter aircraft were received from 1942 onwards . Colder October and November weather limited aerial activities over the NDH . The Partisan operations spread to eastern Serbian territory and the squadrons based at Sarajevo airfield made their appearance on the Bosnian - Serbian border area . The Partisans were trying to secure and expand their territory in the eastern part of Yugoslavia , which they had liberated in the autumn of 1941 . The ZNDH flew daily supply missions with their Avia - Fokker F . 39 and due to the lack of other aircraft also used the venerable Breguets and Potez . These could land on hastily prepared strips and performed very well in airlifting supplies to the surrounded garrison of Višegrad . Expansion : 1942 . In 1942 , fighting with the Partisans intensified . Not only had they liberated a substantial territory in the eastern part of Yugoslavia , but they encouraged rebellion all over the country . The German , Italian and NDH governments were aware of this danger and they used every means available to destroy the Partisan forces . They planned several large - scale operations for this purpose in which air support played a very important role . The first half of 1942 was marked by several deliveries of new or refurbished aircraft from Germany and Italy , aside from those received from Ikarus in Zemun . First of all the ZNDH received 10 brand new Caproni Ca . 311 M medium bombers from Italy . These aircraft had been ordered and paid for by the Yugoslav Government for service in the VVKJ , but the Axis invasion of Yugoslavia prevented delivery . The ZNDH also purchased 20 AVIA F . L . 3 basic trainers , nine Fiat G . 50bis fighters and one Fiat G . 50B two - seat fighter trainer . The Fiat aircraft were to provide the ZNDH ' s fighter pilots with some operational training on more modern aircraft . Other batches of overhauled ex - VVKJ aircraft also arrived from the Ikarus aircraft plant in Zemun , including 11 Dornier Do - 17K , three Bristol Blenheim Mk I and one Caproni Ca . 310 bombers , 15 Rogožarski PVT and 11 Rogožarski R - 100 attack aircraft , which had been fitted with bomb racks to carry bombs , plus a few Breguet 19s , Potez 25s , Zmaj Fizir FN s and Zmaj Fizir FP - 2s . From Prague in Czechoslovakia ( under German occupation ) , the ZNDH received seven Avia Fokker F . 7 transports , one Avia Fokker F . 9 and one Avia Fokker F . 18 . Of these , the F . 7s and F . 18 were pre - war Czech airliners . As the ZNDH suffered from a total lack of transport aircraft , these were immediately pressed into service , after only minor adjustments . Some were even used to provide scheduled air - line services . The nine Fiat G . 50bis fighters took off from Turin - Fiat Aviazione on 12 June 1942 , but before crossing the border they were stopped by an order from " Capo di Stato Maggiore " Cavallero , that was afraid the ZNDH pilots could defect with the new Fiat aircraft . The G . 50 aircraft had to wait until 25 June before being delivered to the 16th Squadron at Banja Luka , but during the course of 1942 , five were transferred to the 1st Squadron stationed in Zagreb in order to strengthen the defence of the NDH capital . Their deployment between the two squadrons was aimed to further familiarise the ZNDH fighter pilots with more sophisticated aircraft . Until that time , the only fighters available in numbers were the seven ancient Avia BH - 33E biplanes and four Ikarus IK - 2 gull wing fighters ( for which there were very few spares ) , as well as 11 Rogožarski R - 100 parasol wing fighter - trainers . Thanks to this extended aircraft park the ZNDH could now form new units : in January the 1st Group , comprising the 1st , 2nd , 3rd and 19th Squadrons was formed at Zagreb , and then the 2nd Group with the 4th , 5th and 6th squadrons and the 3rd Group with the 7th , 8th and 9th Squadrons at Sarajevo ' s Rajlovac airfield , whilst the 6th Group was formed at Banja Luka ' s Zaluzani airfield in June 1942 to cover operations in central Croatia and western Bosnia . These reinforcements came just in time to participate 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 Yugoslavian territory . In support of the ground forces , the ZNDH flew 121 combat missions in January , 100 missions in February and 350 in March . Although the Axis ground forces generally succeeded in their operations in January and February , in March they were forced to release the pressure as other Partisan units attacked several solitary NDH garrisons , threatening to destroy them . Aside from constant bombing sorties , Potez 25 and Breguet 19 aircraft were also used for daily supply missions to the besieged 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 . On 23 March , a ZNDH Potez 25 was shot down by the Partisans and the crew were killed . Three days later an Avia Fokker F . 9 was damaged whilst dropping ammunition to Rogatica but managed to return to base safely . As a result of the determined re - supply effort by the ZNDH , the Rogatica garrison succeeded in holding out until relieved by German - NDH forces on 17 April . As the weather improved towards the summer , flying activity intensified . Some 325 missions were flown during April , with a further 350 sorties during May , including direct combat support , reconnaissance and supply missions , as well as leaflet dropping . 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 . The 10 new Caproni Ca . 311Ms were tried out during the successive attacks on Partisan territory . They were equally divided between 3rd Squadron ( Zagreb ) and 7th Squadron ( Rajlovac ) . During September and October Blenheims from 8th Squadron and the Dornier Do 17Ks from 3rd and 9th Squadrons were extensively used to attack Partisan positions in Bihać , Bugojno , Livno and Duvno and Bosnia . Owing to the availability of increased numbers of aircraft , the 6th Group was formed at Banja Luka comprising the 13th , 16th , 17th and 18th Squadrons . 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 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 machineguns . December 1942 also saw the return of the HZL bomber squadron to Croatia from service on the Eastern Front , where they had flown more than 1 , 500 sorties . Upon its return the squadron was redesignated " 1 . / ( Kroat . ) KG " after having flown its nine Dornier Do 17Z bombers from Russia back to the NDH . The Dorniers proved a welcome addition to the strike power of the Axis forces fighting the Partisans in Yugoslavian territory right up to the end of 1944 . In late 1943 , a second squadron , " 2 . / ( Kroat . ) KG " was formed to provide operational training . It was equipped with Italian designed and built CANT Z . 1007 and Fiat BR . 20 medium bombers . During the course of 1942 , the ZNDH flew some 4 , 800 sorties , of which 30 % were combat missions , with 35 aircraft being lost . Of these losses , 19 were to Partisan ground fire , 12 to accidents and four deserted . By the end of the year the ZNDH aircraft park consisted of 191 aircraft , formed into 14 squadrons . 1942 had seen the first desertions of aircraft from the ZNDH , the first on 23 May when a Breguet and a Potez had defected to the Partisan forces . The army conducted an intensive search for the aircraft and in response the Partisans produced two decoy scale - model aircraft , made of wood and canvas , which were duly destroyed by ZNDH bombers . Both " destroyed " aircraft were able to perform a number of attacks on army units ( armed with hand - made pipe bombs ) before either being shot down ( the Breguet on 4 June ) or destroyed on the ground ( the Potez on 6 July ) . The two other defections occurred in July and October , with a Blenheim bomber in each case flying to Turkey . ZNDH paratroops . In January 1942 , the ZNDH formed a parachute unit , known as the 1st Light Infantry Parachute Company ( , 1 PLS ) . It had a strength of 120 men and was based in the northern town of Koprivnica , near the border with Hungary . An Avia Fokker F . 7 tri - motor transport aircraft was assigned to the unit on a permanent basis , with other transports assigned as required . The paratroops were equipped with rifles , sub - machine guns , light machine guns and light mortars . After a period of training , 1 PLS made a demonstration mass tactical jump on 6 July 1943 at Borongaj airfield , Zagreb . Forty five paratroopers made a successful jump from three Avia Fokker transports . On 6 November 1943 , three brigades of the Partisans , supported by artillery and heavy machine - guns mounted an attack on the town of Koprivnica , which they took on 9 November . The paratroops of 1 PLS held out at their base for three days before withdrawing into Hungary and continuing the battle with other NDH and German defending forces until 29 November . They received direct air support from ZNDH Dornier Do 17Ks , as well as supplies from light aircraft , but were unable to prevent the loss of their base , together with 20 men , all of their parachute equipment and their transport aircraft . The ZNDH also lost a Dornier Do 17K bomber and a Bucker Bu 131 biplane shot down during this period . The unit was re - deployed in 1944 to Borongaj airfield in Zagreb and in June 1944 grew in strength with the addition of three further companies and was re - designated as the 1st Light Infantry Parachute Battalion ( , 1 PLB ) . They were responsible for the ground defence of this important air base and also performed ceremonial guard duties in Zagreb itself . By late January 1945 the unit was equipped with white winter jackets for camouflage and attached to the NDH Motorized Brigade , seeing its first action on this new sector , south of Zagreb . 1 PLB remained in constant action against the advancing Partisans until the last unit surrendered in Austria on 14 May 1945 , one week after the official end of World War II . The balance shifts : 1943 . At the beginning of 1943 the Axis forces had complete control of the airspace over Yugoslavian territory . No aerial opposition of any kind was expected and that was the primary reason that the bomber force could operate without any fighter cover , notwithstanding the fact that there was a total lack of any serious fighter force in the ZNDH ' s squadrons . However , the situation started to change by the beginning of 1943 . The Headquarters ( HQ ) of the ZNDH had plans to re - arm at least one Group with more modern aircraft of German or Italian origin . The Italians refused to supply the requested Macchi C . 200 and Macchi C . 202 fighters , as the Regia Aeronautica needed every aircraft to fill its own squadrons in the beginning of 1943 . This was because the situation began to change in favour of the Allies . They had landed in North Africa while the Soviets were undertaking their great winter offensive , endangering , and eventually defeating , the German 6th Army around Stalingrad . The Partisan movement in Yugoslavia , aside from some smaller territories , established a large liberated territory extending west of the rivers Neretva and Bosna , in the direction of the cities of Zagreb and Rijeka . The Partisan force had grown stronger – it had more than 60 , 000 armed fighters in this so - called " Tito ' s State " who were both well trained and supported by artillery . On 20 January 1943 , the German HQ in Yugoslavia launched an offensive codenamed 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 . The Banja Luka air base was reinforced by a newly formed 5th Group after the end of Case White . The ZNDH now consisted of three air bases with six Groups and 14 squadrons . During 1943 new aircraft continued to arrive , with 30 overhauled Dornier Do 17E bombers delivered from Germany and divided between the 3rd Squadron ( Zagreb ) , and the 13th and 15th Squadrons ( Banja Luka ) . From Italy came 34 long promised ex - VVKJ Bucker Bu 131 Jungmans and 25 Saiman 200 light biplane trainers and liaison aircraft , which were dispatched to all three air bases . They were also used to deliver mail and fresh meat to isolated / surrounded towns and garrisons . Although the ZNDH had a brief role in the subsequent anti - Partisan offensive , Case Black ( ) in mid - 1943 , its main involvement was on the front in the central NDH . As always , the Partisan resistance displayed frustrating survivability and effectiveness and new events started to influence the fighting in Yugoslavia . The Partisan forces were well aware of the constant threat of air attack posed by the ZNDH ' s medium bomber force and on 10 August 1943 undertook a devastating night attack by a brigade on Sarajevo ' s Rajlovac airfield . The three and a half hour assault on the airfield left 10 ZNDH bombers , plus another five Luftwaffe bombers and transports , destroyed , with another 17 aircraft damaged . Although some aircrews returned fire from the machine - gun turrets of their aircraft , Partisan losses were less than 20 . Afterwards ZNDH Command complained that the German ordered dispersal of aircraft around the airfield ' s perimeter , in case of air attack , made the aircraft especially vulnerable to just this type of ground attack . 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 . Mid - September 1943 saw the dismissal of Kren from command of the ZNDH . He was replaced by Lieutenant Colonel Adalbert Rogulja , who initiated a major reorganisation . Following the capitulation of Italy in September 1943 , around 60 Regia Aeronautica aircraft were found at Mostar and Zadar airfields and 33 machines were incorporated into the ZNDH . This number included further Fiat G . 50 fighters , as well as six Fiat CR . 42 biplane fighters . Some CANT Z . 1007 and Fiat BR . 20 bombers were also added into the ZNDH . The Luftwaffe subsequently also supplied the HZL fighter squadron with about 20 - 25 Fiat G . 50s captured by German troops on Regia Aeronautica airfields in the Balkans . The capitulation of Italy also brought with it the real threat of an invasion by the Allies of the Dalmatian coast . As a result on 9 September , orders were received by " 1 . / ( Kroat . ) KG " to execute two coastal reconnaissance sorties over the central and south Adriatic each morning and afternoon . On 10 October one of its Dornier Do 17Zs was intercepted by eight Spitfire Mk . VIII fighters of No . 92 Squadron RAF near the coast of Italy . All of the fighters made firing passes on the Dornier , which was shot down , the crew bailing out . One Spitfire was hit by return fire and crashed into the sea , killing its pilot . After this , reconnaissance sorties were confined to the vicinity of the Dalmatian coast . Attacks on Partisan forces continued , and on 3 October seven Dornier Do - 17Zs 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 60 casualties , including 42 dead . Although the ZNDH was now able to mount a credible threat against the insurgents , by then a new menace was arriving from the other side of the Adriatic . On 30 June 1943 , the first Allied reconnaissance flights were reported , followed by the first USAAF bombers , when 61 B - 24 Liberator s of IX Bomber Command overflew the NDH on a deep penetration raid on the Austrian city of Wiener Neustadt on 13 August . The ZNDH ' s 3rd Flak Group , defending Brod na Savi ( Slavonski Brod ) , managed to shoot down a single bomber en route to its target . The best aircraft that the ZNDH could put up to defend its homeland at the end of 1943 were 20 Morane - Saulnier M . S . 406s , 10 Fiat G . 50s , six Fiat CR . 42s , five Avia BH - 33 s and two Ikarus IK - 2 fighters – aircraft that had been obsolete in 1940 . By the end of 1943 the ZNDH was 9 , 775 strong and equipped with 295 aircraft , having lost 61 shot down , destroyed on the ground , in accidents and five desertions . The Allies strike hard : 1944 . With the capitulation of Italy , the ZNDH lost an important source of new aircraft and the tide turned significantly when Allied air raids on targets in the Balkans became a reality . The Luftwaffe fighter squadrons stationed in Ljubljana , Zagreb , southern Austria and northern Italy fought heavy battles to stop the American USAAF heavy bomber armada . The ZNDH was also included in the defence with the newly formed 11th Fighter Group ( ) consisting of the 21st , 22nd and 23rd Fighter Squadrons ( ) equipped with Morane - Saulnier M . S . 406 and Fiat G . 50 aircraft . 1944 also saw the return of the HZL fighter squadron to the NDH from service on the Eastern Front . It was redesignated " Kroat . JGr 1 " and its operational fighter squadron was redesignated " 2 . / ( Kroat . ) JGr " . Soon after arrival " 2 . / ( Kroat . ) JGr " sent its ZNDH pilots to collect 12 brand new Macchi C . 202 fighters direct from the plant near Milan in Italy . The Italian designed and built Macchi C . 202 fighter was the first up - to - date fighter available to the ZNDH . These aircraft retained their Luftwaffe markings whilst in service with the unit . A second training / operational conversion squadron was also formed , designated " 3 . / ( Kroat . ) JGr " and equipped with Fiat G . 50 , Macchi C . 200 and Fiat CR . 42 fighters . After a period of operational conversion , the squadron commenced operations against the frequent incursions over the NDH by USAAF and RAF aircraft . During a period of intensive activity over the summer of 1944 , the squadron claimed some 20 Allied aircraft shot down , while at the same time receiving six further Macchi C . 202s , as well as four brand new Macchi C . 205 s . The ZNDH ' s long obsolete Morane - Saulnier M . S . 406 and Fiat G . 50 fighter aircraft also attempted to intercept the USAAF bomber formations , often stressing their old engines beyond the limit . They were no match for the escorting Mustang and Thunderbolt USAAF fighters and suffered heavy losses , both in the air and on the ground . By the end of 1944 the HZL squadron had handed in its remaining worn - out Macchis for brand new German Messerschmitt 109G & K fighters . A total of 21 Messerschmitts had been delivered to the ZNDH by year ' s end . 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 . Until then Axis aircraft could fly inland almost at will as long as they remained at low altitude . 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 . In June , the ZNDH finally received from Germany the long - promised airdrop containers ( ) - for aerial resupply of ammunition and other equipment , constantly in need by besieged and encircled garrisons all over the NDH . They were immediately put to good use and eased the work of the already overstretched ZNDH . The Dornier Do 17 s of the ZNDH proved to be especially well suited for such tasks . June also saw Kren returned to his previous position as head of the ZNDH . Toward the end of June , the ZNDH received the first of 22 Bücker Bü 181 Bestmann aircraft . The 19th and 20th Transport Squadrons received five each , with the remainder issued to the 1st Pilot School . Besides liaison duties , they were used to transport fresh meat from Bosnia to Zagreb , where there was a food shortage . Fifteen Ju 87D dive bombers and a few Ju 87R - 2 extended range dive bombers are known to have been supplied to the HZL , and six of these were flown operationally against Soviet troops in the late summer of 1944 . In the second half of 1944 , the situation on all fronts rapidly worsened for the Axis forces . Soviet , Bulgarian and Partisan armies had liberated the whole eastern part of Yugoslavia and Partisan forces in Bosnia pressed their attacks on even larger Axis garrisons . In a surprise attack on 20 September , they captured the city of Banja Luka and the ZNDH ' s airbase at Zaluzani airfield , including 11 unserviceable aircraft . In the total confusion during the attack on the airfield , a number of ZNDH crews managed to take off and escape at the last moment , some even starting their take off runs when barely clear of open hangar doors , using suppressing fire provided by their machine - gun turrets , whilst others took off under heavy Partisan fire . The city and airbase were re - taken several days later in a heavy counter - attack by NDH and German troops . The Germans also continued to supply second - line aircraft to the ZNDH , including between nine and 12 exotic Fieseler Fi 167 biplane torpedo bombers . These had been originally designed and intended for use aboard the German aircraft carrier " Graf Zeppelin " , which was never completed . After that they were sold to the NDH , where their short - field and load - carrying abilities made them ideal not only for attack missions , but also for transporting ammunition and other supplies to besieged army garrisons . Many of these missions were flown between their arrival in September 1944 and the end of the War ( under the right conditions , the aircraft could descend almost vertically ) . During one such mission , near Sisak on 10 October 1944 , an Fi 167 of the ZNDH was attacked by five P - 51 Mustang Mk IIIs of 213 Squadron RAF . The crew of the Fieseler ( piloted by an ex - HZL eight - kill Flying ace ) , exploiting the aircraft ' s extreme maneuverability to the fullest , had the distinction of shooting down one of the Mustangs before itself being shot down ; possibly one of the last biplane " kills " of the war . Death of an air force : 1945 . 1944 had been a catastrophic year for the ZNDH . Aircraft losses amounted to 234 , primarily on the ground , and it entered 1945 with 196 machines , including 17 Messerschmitt 109Gs , 12 Morane - Saulnier M . S . 406s , seven Fiat G . 50s and two Fiat CR . 42 fighters and some 30 multi - engined bombers , although shortages of fuel had begun to hamper operations . Further deliveries of new aircraft from Germany continued in the early months of 1945 to replace losses . Some 39 by the end of March . These included , in addition to regular Messerschmitt 109G deliveries , the final dozen Dornier Do 17 medium bombers in January . In March , despite losses of 15 Messerschmitt 109G & Ks , ten Morane - Saulnier M . S . 406 , three Fiat CR . 42 and two Fiat G . 50 , the ZNDH ' s fighter force included 23 Messerschmitt 109G & Ks , three Morane - Saulnier M . S . 406 , six Fiat G . 50 and two Messerschmitt 110G fighters . With the Messerschmitt 109G the ZNDH were finally able to face the USAAF and RAF on equal terms , with two squadrons equipped with the type from late 1944 . The ZNDH still had 176 aircraft on its strength in April 1945 . 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 , after a bridge - busting sortie on the Drava river , a single ZNDH Dornier Do 17Z caught " 1 . Zagorska Brigada " ( 1st Zagorje Brigade ) marching in the open near Daruvar . The Yugoslav Partisans ( by now known as the " Jugoslovenska Armija " - Yugoslav Army ) unit suffered some two dozen casualties . Late in the afternoon of 30 March , four Dornier Do 17Z bombers , escorted by four Messerschmitt 109G fighters attacked " Jugoslovenska Armija " positions near Gospić . On 15 April 1945 , a force made up of a Dornier Do 17Z , escorted by two Messerschmitt 109Gs destroyed two Partisan aircraft at their airfield at Sanski Most . Despite these attacking raids , with the outcome of the war by now quite obvious , defections of ZNDH personnel and aircraft to the Allies and Partisans intensified , including two Messerschmitt 109s to Italy on 16 April and a further two Messerschmitts to the Partisans in Mostar on 20 April . The last fighter delivery took place on 23 April 1945 . It was also on this day that the final Croatian kills were scored when an ex - HZL 16 - kill ace and his wingman claimed two RAF P - 51 Mustangs shot down in their Messerschmitt 109Gs , one of which was confirmed . The last attack mission was flown on 6 May , when two ancient Rogožarski R - 100 fighter trainers bombed the railway bridge over the Kupa River in an effort to stop the Partisan advance on Karlovac , south of Zagreb . One of the Yugoslav - built parasol wing aircraft was hit by ground fire and the pilot crash - landed near his target . He was captured and shot on the spot . That evening , with Partisan forces advancing upon the NDH capital of Zagreb , the commanding officer of the ZNDH fighter group gathered together his men at Zagreb ' s Lucko airfield and released them from their oath of loyalty and announced that each was free to go . Some flew their aircraft and crews , including several Dornier Do 17s and a CANT Z . 1007 to Italy and the Allied forces there . Some flew their aircraft over to the Partisans , including several light aircraft and some Messerschmitt 109s , whilst others , also including Messerschmitt 109s , as well as at least one Dornier Do - 17Z , a Messerschmitt Me 110G - 2 , a Bristol Blenheim I and a Yugoslav - designed and built Zmaj Fizir FP - 2 sought sanctuary at Klagenfurt in Austria . The four - year campaign of the ZNDH , during which it had on its charge at one time or another some 650 aircraft , thus ended with the capture of the airbases around Zagreb on 8 May 1945 and the ZNDH ceased to exist . Its colourful collection of often vintage aircraft , scattered on deserted airfields , received new markings , a red star , and formed the basis of the new Yugoslav Air Force . Journal . The ZNDH published a weekly journal called " Hrvatska Krila " ( Croatian Wings ) .