The PZL P.11 served as the main Polish fighter for defense during the Polish campaign in 1939. About one hundred was in service by 1st September 1939 in Poland.
The PZL.23 Karaś was a Polish light bomber and reconnaissance aircraft designed in the early 30s by PZL in Warsaw. About 25 were built.
The PZL.37 Łoś was a Polish twin-engined medium bomber designed and manufactured by national aircraft company PZL. Polish Air Force had about 86 PZL.37s in total by 1st September 1939.