Niš Constantine the Great Airport, located 4 km northwest of downtown Niš, in the suburbs of Medoševac and Popovac. It is the second-largest and second-busiest airport in Serbia, after Belgrade Nikola Tesla Airport. Niš Military Air Base, the Serbian-Russian Emergency Response Centre and Centre for Aerial Firefighting Duties are all located on the site of t…Niš Constantine the Great Airport, located 4 km northwest of downtown Niš, in the suburbs of Medoševac and Popovac. It is the second-largest and second-busiest airport in Serbia, after Belgrade Nikola Tesla Airport. Niš Military Air Base, the Serbian-Russian Emergency Response Centre and Centre for Aerial Firefighting Duties are all located on the site of the airport.