Career
The two began repairing planes in a workshop within the complex of an old sugar factory in Prague. One year later, they designed their first two-seater plane: the Avia BH-1. From 1923 to 1925, the two developed the Avia BH-7, BH-9, and BH-11 monoplanes, launching the era of biplane fighters.
Three years later, their Avia BH-21 fighter was considered one of the world"s best planes.
In 1930, Hajn and Beneš came to ČKD-Praga. The first aircraft they designed was the Praga East-39 in 1931.