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.

Its commander was Colonel Vladimir Kren, a former captain of the Royal Yugoslav Air Force (Serbo-Croatian: Vazduhoplovstvo Vojske Kraljevine Jugoslavije; VVKJ),[3] who had defected to the Germans in Graz in his Potez 25 on 4 April 1941 and declared himself an Ustaše supporter.

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.

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.

[6] 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.

[8] 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.

[9] The emblem of the ZNDH was to be the red and white chequerboard insignia, (Croatian: Šahovnica), derived from the Croat coat of arms, dating back to the 10th century, carried on the fin.

[9] 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 12 kilograms (26 lb) bombs.

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.

[10] The ZNDH's fighter force was poorly equipped in every respect, consisting of 12 ex-VVKJ machines including four Ikarus IK-2s, seven ancient Avia BH-33 Es and one Hawker Fury II.

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 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.

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.

[23] 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 (Croatian: 1 Padobranska lovačka bojna, 1 PLB).

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.

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.

From Italy came 34 long promised ex-VVKJ Bücker Bü 131 Jungmans and 25 Saiman 200 light biplane trainers and liaison aircraft, which were dispatched to all three air bases.

[27] Although the ZNDH had a brief role in the subsequent anti-Partisan offensive, Case Black (German: Fall Schwarz) in mid-1943, its main involvement was on the front in the central NDH.

[29] 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.

[35] 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.

[38] 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.

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.

After that they were sold to the NDH,[43] 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.

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.

On 31 December 1944, a Dornier Do 17E destroyed an RAF 148 Squadron Handley Page Halifax bomber on the ground at the Partisan airfield in Grabovnica, near Čazma.

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 Bf 109Gs, one of which was confirmed.

The last attack mission was flown on 6 May, when two antiquated Rogožarski R-100 fighter trainers bombed the railway bridge over the Kupa in an effort to stop the Partisan advance on Karlovac, south of Zagreb.

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.