An air army was a type of formation of the Soviet Air Forces from 1936 until the dissolution of the USSR in 1991. Air armies continued to be used in the successor Russian Air Force until 2009, and, with a brief break under Serdyukov, from 2015. Also formed were the Air Armies of the Air Defence Forces (PVO), which combined all of the air formations and units of the military districts, and operated predominantly interceptor fighter aircraft. Many of these formations and units were subsequently transferred to the Frontal Air Armies.