The airfield lies in the Hron valley between Zvolen and Banská Bystrica, about 3 km north-west of the spa town of Sliač. Until 1945 it was called Tri Duby, the Three Oaks. When it was founded is not settled in the sources used here: German Wikipedia says it has been a military airfield since 1924, in Czechoslovak times, while English Wikipedia states that the airport was built in 1957. Neither statement is referenced to an official source, and the 1957 date is contradicted by the airfield’s well-documented wartime use.

What is certain is that Tri Duby was in military use by 1939. When Hungary attacked the new Slovak State in March 1939, the Slovak air arm dispersed the 3rd Air Regiment across several fields, Tri Duby among them, according to the English Wikipedia account of the Slovak–Hungarian War. The brief war went badly in the air: Slovakia lost nine fighters destroyed or damaged, and on 24 March Hungarian bombers struck the main base at Spišská Nová Ves, where 13 victims, some of them civilians, were buried three days later.

The central location that made Tri Duby useful in 1939 made it decisive five years later. Surrounded by the mountains of central Slovakia and close to the insurgent capital, Banská Bystrica, it became in the autumn of 1944 the one place from which a cut-off uprising could be reached by air. The airfield’s wartime name survives in Slovak memory, and the Ministry of Defence’s Museum of the Slovak National Uprising in nearby Banská Bystrica tells the story of the airlift that ran through it.

The Slovak National Uprising began on 29 August 1944. Airmen who joined it formed the Slovak Insurgent Air Force, whose Combined Squadron gathered a mixed collection: four Avia B-534 biplanes, three Letov Š-328s, two elderly Bf 109E-4s, later two Bf 109G-6s, a Fw 189, light aircraft and two SM.84 bombers. From 6 September to 25 October 1944 Tri Duby was its main base, with the airfield at Zolná near Zvolen as the second.

The insurgents’ first air victory came on 2 September, when Master Sergeant František Cyprich, test-flying a repaired B-534, shot down a Ju 52 transport in Hungarian markings. English Wikipedia records it as the last air-to-air victory by a biplane fighter. Across the whole campaign the insurgent pilots are credited with 923 sorties and 40 Axis aircraft destroyed; these figures come from a secondary account and are not broken down by airfield.

On 17 September the Soviet command sent in the 1st Czechoslovak Fighter Air Regiment under Captain František Fajtl, who had flown with the RAF, flying Lavochkin La-5FN fighters. English Wikipedia gives the regiment 20 pilots in its article on Fajtl and 21 fighter aircraft in its article on the uprising; the exact number that reached Slovakia is not settled. Fajtl’s biography says the Germans at first did not realise a fighter unit was operating inside the insurgent territory.

As German forces closed in, Tri Duby became the last airfield in insurgent hands and came under artillery fire. It was given up on 25 October 1944; the last two B-534s there were burned as the base was evacuated, and the surviving pilots withdrew to airfields held by the Red Army in Poland. The uprising itself was crushed by the end of October.

Tri Duby mattered less for the few fighters based there than for what came in. The Museum of the Slovak National Uprising in Banská Bystrica, an institution of the Ministry of Defence, counts 1,199 flights by Soviet long-range aviation to insurgent territory between 4 September and 24 October 1944, of which about 682 were successful. They carried up to 2,000 people and 639.1 tonnes of material.

The largest single cargo was the 2nd Czechoslovak Parachute Brigade, which the Soviet Li-2 transports brought in together with Allied aid. English Wikipedia puts the brigade at about 2,000 well-trained and equipped men, who arrived gradually over several weeks rather than as one decisive force. A Li-2 now stands outside the museum’s entrance, and visitors can climb aboard the cabin of the aircraft that symbolises the airbridge.

Help also came from the West. According to English Wikipedia, American supplies and agents of the Office of Strategic Services arrived through Tri Duby, and the airfield was used to fly out American airmen who had escaped German captivity or come down over the area; its article on the uprising says American and British aircraft landed twice near Banská Bystrica for such evacuations. The dates and aircraft numbers of these flights were not confirmed from a primary source for this page.

Renamed Sliač in 1945, the airfield served the Czechoslovak Air Force, whose MiG-15, MiG-19, Su-7 and MiG-21 types are listed for the base by English Wikipedia. After the Warsaw Pact invasion that ended the Prague Spring in 1968, Sliač became a base of the Soviet air forces. Until 1990 it hosted Soviet fighter-bomber and reconnaissance units flying MiG-23s, MiG-29s and Su-22s; the regiment numbers are not confirmed here.

The Soviets left in 1990. In 1991, according to German Wikipedia, a Czechoslovak unit flying MiG-21MF, MiG-21UM and MiG-21US fighters and a few L-39ZA trainers moved in. When Czechoslovakia divided its air force, Slovakia’s share of the MiG-29 fleet arrived at Sliač in December 1992, and The Aviationist dates the 1st Fighter Squadron to October 1992. German Wikipedia says the 1st Fighter Regiment was formed at the base on 1 January 1993, the day Slovakia became independent.

Designations changed often. The Aviationist records the squadron becoming the 311th Fighter Squadron of the 31st Fighter Wing in early 1995 and the 1st Fighter Squadron of the Fighter Wing in October 2001; German Wikipedia dates the 31st Wing to 1994. The last MiG-21s were retired in 2002, and on 28 August 2002 the base took the name of Otto Smik, the highest-scoring Slovak fighter ace of the RAF. Today the 81st Wing is its parent unit, and its official number and title have not been confirmed from an official Slovak source here.

For three decades the MiG-29 at Sliač was Slovakia’s only supersonic fighter and the core of its air policing. The Aviationist counts 52 pilots trained and about 20,246 flight hours on the type. It also puts the fleet at 12 aircraft when it was retired, and reports that fewer than a dozen were airworthy. Slovakia later approved the transfer of 13, so the sources differ on how many airframes were on hand: the larger figure appears to include jets that were not flying.

The Fulcrums flew their farewell at the Slovak International Air Fest at Malacky on 27–28 August 2022 and were grounded on 1 September 2022. Defence Minister Jaroslav Naď had said the fighters would guard Slovak airspace from Sliač until the end of August. Under an agreement signed on 27 August, Czech and Polish fighters took over the policing of Slovak airspace until the F-16s arrived.

On 17 March 2023 the government approved giving 13 MiG-29s to Ukraine. Ukrainian mechanics prepared the jets at Sliač, and on 23 March Ukrainian pilots flew the first four out, with their Slovak markings removed. The Aviationist reported that the rest would go by land, and noted that Ukraine already flew the type, so its pilots needed no conversion training. Naď wrote that he hoped they would “save many lives”.

Sliač has been rebuilt twice in fifteen years. From 2009 to 2011 the runway and facilities were rebuilt with NATO and European Union money, and the base reopened to military flying in May 2011 and to civil flights in June 2011. The civil side never became viable: summer charters carried between 24,165 and 41,866 passengers a year from 2013 to 2019, traffic ended in October 2021, and the operating company went bankrupt in 2022, according to English Wikipedia.

A second modernisation for the F-16 Block 70 began in 2019; German Wikipedia, citing Janes, puts the cost at 55 million euros. In February 2022 parliament approved a Defence Cooperation Agreement letting US forces use Sliač and Malacky-Kuchyňa for ten years, with 100 million US dollars from the US to modernise them. The vote was 79 to 60, and thousands protested outside parliament; opponents said it threatened sovereignty, which the US Secretary of State denied.

Weeks later, after Russia invaded Ukraine, NATO sent a German-Dutch Patriot air and missile defence task force to positions near Sliač. The Bundeswehr said the deployment began in mid-March 2022, while NATO’s air command announced on 14 April that the task force would arrive later that month. Germany’s Air Missile Defence Wing 1 supplied two of the three Patriot squadrons and the Netherlands the third. German Wikipedia says the Patriots left in 2023.

The rebuilding meant that Slovakia’s first F-16s, arriving on 22 July 2024, landed at Malacky instead, and the 81st Wing’s fighters and trainers still fly from there. After the IMAD 2026 air show in September 2026 the defence minister, Robert Kaliňák, said he expected to open Sliač ceremonially “next year”, and suggested that future air days should return to the base.