During 1943-44 the EAM/ELAS had created at least two airstrips in the northern part of Greece and some flights took place from and to there. The most important was Neraida airstrip near Karditsa where there is only one recorded flight from a Li-2 carrying Col Popov and his staff who came for negotiations with EAM (the political part of EAM/ELAS) and finaly stayed as the USSR military attache in Athens for many years. These airstrips were straffed by the forces of the Gonverment, but only for psychological reasons. The government forces were equaly reluctant to make any fighting with forces of Albania and Yugoslavia for avoidance of great powers intervention.
The Spitfire incident took place, if I am not mistaken, in 1947 but I have to look up to it. The pilot forced landed and was unhurt and later on was brought back in Greece.