4 decal variants:
1. Praga E 39.56, Hlinkova letecká garda, airfield Spišská Nová Ves, October, 1939
2. Praga E 39, airfield Piešťany, 1941
3. Praga E 39.126, airfield Piešťany, 1943
4. Praga E 39, airfield Tri Duby, 1944
The E 39 proved so succesfull that the MNO (Ministry of Defense) placed a order for the machine in December 1933. First 8 examples were build in Letov next 13 powered by an 140 hp Walter Gemma radial engine in Praga factory. During 1936 MNO ordered next 85 aircraft and 10 for civil clubs. The other production model was powered by a 160 hp Armstrong Siddeley Genet Major ergine. Total pre-wartime production was 139 aircraft from this was 10 machines produced after German annexation for Slovakian A.F. Here were used as trainer and reconnaissance as operational on the Eastern Front. Luftwaffe used extensively 125 machines as primary trainers in more A/B schools. Some machines were sold to Hungary and here flown in civil clubs. After war flew in Czechoslovakia only one machine in airfield Kralupy.