Military aviation in free Poland started even before officially acknowledged date of regaining independence (11 November 1918). Poland was under German and Austro-Hungarian occupation until the armistice, but the Poles started to take control as the Central Powers collapsed. Initially, Polish air force consisted of mostly German and Austrian aircraft left by former occupants or captured from them, mostly during the Greater Poland Uprising. They were first used in a conflict with Ukraine around Lwów (now Lviv) in late 1918. On 2 November Polish units took over an airfield Lewandówka in Lviv, and on 5 November 1918 pilot Stefan Bastyr performed the first combat flight of Polish aircraft (Oeffag C.II). Other actions included the retaliatory bombing of an airfield in Frankfurt (Oder) on 9 January 1919 by LVG C.V aircraft during the Greater Poland Uprising.