Cold War Era

Italian F-84Gs Vs Yugoslav F-84Gs: how Italian and Yugoslav Thunderjets almost fought each other during Trieste crisis’s air war that never was

As Yugoslav jets were flying above Yugoslav Air Force’s base in Cerklje, the ground personnel panicked – they were not even informed about the usage of Thunderjets in their country’s air force; therefore, they automatically thought that the F-84s belonged to the Italian Air Force.

Free Territory of Trieste was a political unit in the nowadays Italian city of Trieste, located on the relatively short common borders between Italy and Yugoslavia. Even though de iure it was a political entity, which was created as the result of the chaos brought to Europe after the end of the Second World War, de facto it was a region divided between two sides – the western allies (US, UK and Italy) and Yugoslavia – the new socialist federation in the western Balkans. As the Trieste problem remained unsolved for almost a decade after the war had ended, new tensions had risen – between Italians and Yugoslavs. Shortly before the crisis had reached its peak, both sides were armed by the US, via the Mutual Defense Assistance Program. Even though the conflict fortunately didn’t erupt, it brought an interesting question – since both countries fielded the same jet fighter in the guise of the F-84G Thunderjet, how would the air war of this hypothetical conflict have looked like? 

As I would like to focus this article on the usage of Republic’s Thunderjets by the air forces of both Italy and Yugoslavia, I’ll just briefly sum up the basic geo-political background of the crisis and the statehood of the Free Territory of Trieste. The Trieste’s area has been in the eyes of both Italy and Yugoslavia since the end of the Second World War. Even though the city itself and the surrounding area had much larger Italian population than Yugoslavian (Slovenian and Croatian to be more specific), the area was captured on May 1, 1945 by Slovenian partisan forces after fighting between German and Tito’s Yugoslav forces. The British-American forces, coming from the west, had made an agreement with Yugoslavia – the city would be neither part of Italy, neither of Yugoslavia. Trieste and the surrounding area became known as Free Territory of Trieste, divided into two zones – Zone A (administered by The Allied Military Government) and Zone B (administered by Yugoslav officials). However, the importance of this north-east Adriatic port was well known for both Italy and Yugoslavia. So, the tensions and arguments about the future of the Territory began in the fall of 1953.

Both Italy and Yugoslavia received their first post-war aircraft by foreign aid. In the case of Italy, the main suppliers were the UK and the US. Ex-USAAF Mustangs and Thunderbolts were the first fighters which the re-borned Italian Air Force received, followed by the service first jets – British de Havilland Vampires and American F-86D Sabres and F-84G Thunderjets. The aircraft created the backbone of the country’s air force. Italy received its first Thunderjets in May of 1952. The Italian Air Force, in the dawn of the hypothetical conflict, disposed its F-84Gs into three Air Brigades (equivalent to US Air Force’s squadrons) – to Verona-Villafranca (5 Aerobrigata; around 230 km to Trieste), Ghedi-Montichiari (6 Aerobrigata; around 260 km to Trieste) and Aviano (51 Aerobrigata; just around 100 km to Trieste). Combined, all three Air Brigades subordinated to the 56th Tactical Air Force (with headquarters stationed in Vicenza), consisted of around 180 F-84Gs, which were in relatively close range to Trieste. Italian Air Force, in overall, was equipped with 254 F-84Gs.

Free Territory of Trieste – the region, which was almost one of the first theaters of post world war two conflict. Zone A is the area controlled by the western allies units; Zone B was on the other hand controlled by Yugoslavia

Same as in the case of Italy, Yugoslavia built its post-war air force on foreign aircraft, even though the most common fighter type was Yugoslav Ikarus S-49C. The Mutual Defense Assistance Program allowed Yugoslavs to get British Mosquitoes and American Thunderbolts, followed by ex-USAF Sabres, Thunderjets and T-33s. The first F-84Gs for Yugoslavia were delivered to the country’s air force 9 Jun. 9, 1953. The rest of the aircraft were being delivered in small amounts until October of the year.  The Yugoslav Air Force’s fleet of F-84G jet fighters (F-86D Sabres were not yet ready to be used during the crisis) was not just weaker on paper, but also in reality. At the time of the crisis it operated just 54 Thunderjets – and all were stationed in Batajnica (near capital Belgrade, around 525 km to Trieste, serving under 117th and 204th Aviation Regiment). Taking in mind the fact that F-84G’s combat range is around 1’600 km (with a ferry rage of 3’200 km), and the fact that if needed, the Yugoslav Thunderjets could use Zagreb-Pleso air base (179 km to Trieste) in Croatia, the large distance of the main base doesn’t seem like large disadvantage for the socialist air force. However, in a long-lasting conflict where more sorties would need to be flown, location of the headquarters of the unit was being a big disadvantage. Even though 14 Thunderjets were deployed in November to Zagreb-Pleso, the number of the deployed jets would not play a large role, compared to the around 180 Thunderjets of the Italian Air Force. A team of Yugoslav Air Force was also dispatched to find suitable parts of the Belgrade-Zagreb motorway which could be used for the F-84G landings in the case that the conflict with Italy would be widened.

The unreadiness of the whole Yugoslav Air Force’s personnel is best shown on one particular occasion. The Thunderjets from Zagreb-Pleso flew several ‘show-off’ sorties over Slovenia, while also flying over Yugoslav Air Force’s base in Cerklje (equipped with Il-2s and F-47D). As the jets were flying above the air base of its own air force, the ground personnel panicked – they were not even informed about the usage of Thunderjets in their country’s air force; therefore, they automatically thought that the F-84s belonged to the Italian Air Force.

Another problem for Yugoslav Air Force and its fleet of Thunderjets was the slow progressing conversion of the pilots to the new jets. During the crisis, a few Thunderjets pilots went through just a few gunnery exercises and cement-bomb drops practises. After the arrival of 14 F-84Gs and their pilots to Zagreb-Pleso, gunnery practices continued by using an aerial targets (towed by F-47Ds), while the close-air-support practise went to the stage of using HVAR 5-in unguided rockets on ground targets. One of the Yugoslav Thunderjet pilots, Predrag Vulić, remembered that “… we had the airplanes with radar and gyroscope sights. No one among the pilots didn’t know how to use the sight. We also had minor knowledge in firing manoeuvres too.”

On the edge of the crisis Yugoslav Air Force flew several reconnaissance missions with de Havilland Mosquitos over Italian territory, with seven sorties being noted by the Italian air defense. The Italian side also flew reconnaissance missions over Yugoslavia – 23 Italian flights were registered, however, no more details about which aircraft were used in those violations can’t be found, the Thunderjets were probably not used. On one occasion of Italian violation, two Yugoslav F-84Gs from Zagreb-Pleso took off, as they were ordered to confirm the visual sight and to catch Italian aircraft, reported being over Yugoslav land on Nov. 26. As it took nine minutes for the Yugoslav jets to take off, the Italian aircraft already left the area. In the case the Italian aircraft would be caught, the Yugoslav pilots would not probably even react (shoot to be more specific) unless ‘fired at first’. The reason for this rule of engagement was the downing of a US Army Air Force’s C-47 over Slovenia by Yugoslav fighters in 1946, which caused relatively high tension between the west and Yugoslavia.

F-84G Thunderjet of Yugoslav Air Force in the Military History Park in Pivka (Slovenia) (author Jaroslav Cabuk)

Duel: Italian vs Yugoslav F-84Gs

Unlike Yugoslavia, Italy didn’t have much problems with the operational service of their Thunderjets. As Italy received its first jets a year before Yugoslavia, the Italian pilots had more time to learn to fly the 1st generation jet aircraft than their Yugoslav counterparts. The very important aspect is the training itself, which was again of much higher quality in Italy. Italy, as one of the NATO members, was collaborating also with its western allies. Yugoslavia, which after the break up between Tito and Stalin, came on its own ‘lonely’ way, was forced to be trained on the new aircraft de facto alone. Even though the American personnel played a significant role in the Yugoslav pilots training, the level of quality of the training in Yugoslav Air Force never reached that of the Italians.

Northern Italy was covered by much better air bases and air strips, which could be used for operational service of the upcoming aircraft. Unlike Yugoslavia, before the Second World War the Mussolini’s regime invested large money and time to modernize not just the air force, but also its air bases. Even though Yugoslavia had its own air force before the world war, the air bases were not ready to host the new-era aircraft, powered by jet engines. Yugoslavia therefore after the end of the war found itself with just one modernized air base, suitable for operating such aircraft – Batajnica air base near Belgrade. Even the Zagreb-Pleso air base, which served as an air base for 14 Thunderjets, had to be enlarged, before the first F-84Gs started to fly from it.

If a war had broken out between Italy and Yugoslavia the Thunderjets would have been effectively used probably just by Italy. Many of its F-84Gs could operate from three air bases located less than 300 km from Trieste, which would have led to a high number of sorties that would have to be flown in case of a conflict. Yugoslavia, on the other hand, had only one quarter of the Thunderjets compared to Italy. The important thing is to note that only 14 of them were able to fly combat operations, as they were piloted by the already trained pilots. While Batajnica being more than 500 km away from the hypothetical combat zone, the only air base suitable for the operation was in Croatia. It’s unlikely that the Yugoslav Air Force would use its valuable jet aircraft in the direct confrontation, unless the whole fleet of its fighter jets, consisting of the Thunderjets and Sabres, would be ready. But again, the important logistical topic pops out. Probably the only aircraft, which Yugoslavia would use against Italian Air Force in the dogfights would be the piston-powered Ikarus S-49. Even though Yugoslavia has operated Bf-109Gs and Spitfires after the end of the war, the potential use of these world war two aircraft against Italian jets was unlikely.

The crisis fortunately ended without any intervention between Italian and Yugoslav Armed Forces by dividing the area between both Italy and Yugoslavia. Even though it might seem that the conflict was unlikely to happen, escalation of political and military tension between Italy and Yugoslavia in the early 50s was on the same level, as the first Berlin Crisis and escalation of tension between the western allies and the Soviet Union. However, in the case of hypothetical war, were both sides would be armed with F-84Gs as their first jet aircraft, we can by this short analysis say that the sky over Trieste would be dominated by the Italian Thunderjets.


F-84G Thunderjet of Italian Air Force in Vigna di Valle (Italy) (author Simon Brooke via
Jaroslav Cabuk

Jaroslav Cabuk is working in the Ministry of Defense of the Slovak Republic, under the Section of Defense Policy. He studied Defense studies in Slovakia as well as Military and defense studies in Slovenia. His interests are mostly into the Eastern Europe aviation and aviation history, especially the region of V4 countries and Balkans. The military history of these regions were the main subjects of his previous University's works.

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