12 Polish fighter squadrons were equipped with this fighter at the out break of WW2 in September 1939.
The P.11 fighters suffered heavy losses. Nevertheless, they scored 125 Kills against the Luftwaffe, and lost 114 in the process.
Later, when the Soviet Union over run Poland, some fighters were evacuated to Rumania and entered service.
When Germany launched it's offensive against the Soviet Union in July 1941, Rumanian forces fought on the Axis side. 5 Squadrons of Rumania were still equipped with the P.11, but they never saw action, they were used for home defense and fighter training until 1942.
