ČKD-Praga was a Czechoslovakian aircraft manufacturer. The company was founded in 1915 as an engine manufacturing company under the designation Praga. The company started designing aircraft in 1930–31 when the designers Pavel Beneš and Miroslav Hajn came to ČKD-Praga from Avia. Their first aircraft was the Praga E-39 from 1931. It was a military trainer with a production run of 139 aircraft. ČKD-Praga developed several aircraft over the following years but none exceeded prototype stage.