[1] This aircraft was designed by Pavel Beneš and Miroslav Hajn, engineers at the Czech aviation company ČKD-Praga in 1931.

The biplane, standard configuration for that era, was an immediate success and orders were placed by the Czechoslovak Air Force that used them as elementary training aircraft at its flight schools throughout the 1930s.

[3] In 1939 following the German occupation of Bohemia and Moravia, Slovakia became an independent country.

It was a German ally and its small air force was placed under Luftwaffe control.

Other E-39s were used by the Luftwaffe in their flight training schools as elementary trainers, and still others were given to the Hungarian Air Force for use in that same role.