Dukovac was born in September 1918 in Surčin , Kingdom of Croatia-Slavonia , Kingdom of Hungary , Austria-Hungary (today Belgrade Region , Serbia ). He enlisted in the Croatian Air Force soon after the country was declared independent in 1941. After training he was posted to the Kuban front in Russia with the Croatian Legion , flying his first mission on 29 October 1942.
After scoring some early combat successes against the Soviet Air Force , his potential was recognised by Cvitan Galić , the leading Croatian ace at the time. Thereafter the two men partnered one another in a pair formation, known as a Rotte , together becoming the two most successful Croatian pilots.
In February 1944 Dukovac flew his 250th mission, scoring his 37th confirmed kill, for which he was awarded the German Cross in gold by Field Marshal Wolfram von Richthofen in person. Later that year, during the Soviet offensive in the Crimea , his tally of kills rose to 44, making him the number one Croatian ace ahead of Galić.
In August 1944 he was promoted to the rank of captain and sent with a contingent of the Croatian Legion to Eichwalde in East Prussia . While training in the use of the latest models of the Messerschmitt Bf 109 at Flugplatz Eichwalde in Eastern Prussia he deserted to the Soviets on 29 September 1944.
He served as a time as a flight instructor with the Soviet Air Force before being sent with other Croats to Pančevo in Serbia in December 1944, also as a flying instructor. In February 1945, for his previous service with the Axis powers , he was supposed to be arrested. He escaped the arrest and flew to Italy on 8 August 1945 with a stolen de Havilland Tiger Moth , where he surrendered to the Americans.  He was treated as a Luftwaffe prisoner of war.
In January 1946 he went to Syria and joined the Syrian Air Force . He fought in the 1948 Arab-Israeli War flying initial missions as part of the 1st Aerial Squadron, flying Canadian–built T-6 Harvard trainers, armed with two 0.303 Browning machine-guns, from al Mezze airfield near Damascus . His only aerial claim occurred on a reconnaissance mission, an Israeli scout aircraft thought to be a Fairchild 24 .
In late 1948 he emigrated to Toronto in Canada and settled there, raising a family. He commenced a business career with IBM . In 1979 he attended a Luftwaffe anniversary in Munich . In Canada, Dukovac founded an association of Croatian Canadians called "United Canadian Croats". He died in September 1990.