The regiment and brigade size units were main units of SFR Yugoslav Air Force during its existence, as parts of aviation divisions, commands and corps. Aviation regiments until "Drvar" reorganizations composed from three aircraft squadrons and one technical squadron, but after they composed from two to five aircraft squadrons. By the middle 1960s, some regiments had become brigades as they composed from more squadrons. They were equal to a USAF wing or RAF group. In organization of the Yugoslav Air Force there were also other branch regiments and regiments, as signal, air reconnaissance/intelligence and guidance, air defense and paratroop.