Residents of the Zvolen region were already familiar with aviation because of its introduction during the reign of the Austro-Hungarian Empire. The first “so called” airport to be established in the region was located close by, near to the neighbouring village, Veľká Lúka. It soon became quite clear that a more suitable location was needed as the interest in, and demand for aviation persistently increased. Land was eventually acquired on the outskirts of Sliač which was ideal due to its territorial location and so, named after an adjacent farm… “Three Oaks” airport was established.
The first military aircraft to land at Tri Duby “Three Oaks” flew in on 15th July 1935 although 1st May 1936 is considered to be the official beginning of aviation in the district. Air crews took residence on 1st September 1937 and construction of barracks began in 1938 along the bank of the nearby river Hron. An important task of the airport was to train new pilots at the Czechoslovak Aero Club. In April 1936 the airport acquired 3 aircraft from the national aviation school which lead to the construction of the airports’ first hangar. During these early years, two highly skilled Czechoslovakian pilots who were recognised for their superb aerobatic skills; major Ambrus and Lieutenant Trnka, took up local residency.
During World War II, the airport was bombed several times, being severely damaged on two occasions but continued to operate throughout the war. Tri Duby airport played a crucial role during the 1944 (SNP) Slovak National Uprising. Even before the outbreak of the uprising, local crews at the airport prepared for the event. Machine guns were fitted to old scrap machinery which was disguised and concealed behind curtains in the hangars. Between 25th September & 16th October 1944, Sliač temporarily became one of the busiest airports in the world. During this period, 1,739 people and 248 tons of weapons were airlifted in an out of the airport. During the night of 5th/6th October, 162 aircraft arrived and departed. British and American forces brought medication and much needed armour-piercing weaponry. On 17th September, 4 American B-17 bombers landed which carried the US military liaison mission team and on the 7th October a further 6 American B-17 bombers landed, which brought in additional military and medical supplies.
The military section of the airport is named after Otto Smik, a Czechoslovakian pilot who served with the British (RAF) Royal Air Force during World War II. From 1934, he resided in the nearby town of Sliač along with his parents.
On the 21st March 1945, the airport changed its name from Tri Duby "Three Oaks" the name we are all familiar with to this day, Sliač.
Civilian aviation activity at the airport began in 1947 and continues to operate to this day.
In 1968, Sliač airport and all adjacent land was acquired and controlled by the invading Soviet forces with the exception of the civil sector, which remained under the administration of state owned, Czechoslovakian Airlines. In the early days of the occupation, traffic at the airport increased significantly. Activity included heavy transport aircraft, fighter jets and heavy duty combat helicopters; this situation remained unchanged for over 20 years. In 1989, during the Velvet Revolution, Soviet troops were granted, with international agreement, to vacate Sliač airport and all of its associated premises within 1 year. Upon the departure of Soviet troops, the airport was returned back to the Czechoslovakian air force.
In 1991 Sliač airport was granted the status of an “international” airport.