Formed 1915 as Breitfeld, Danek & Co. to build Hiero aero engines. Expanded to design own engines, trade name Praga, and also produce armaments. Changed name to Ceskomoravska-Kolben-Danek and opened Aviation Dept. April 1931 to produce aircraft of own design, adopting name CKD-Praga and aircraft known simply as Praga. Benes and Hajn joined from Avia and designed BH.39 biplane trainer (several versions). Other military biplanes included E.36 bomber, E.40 primary trainer, BH.41 advanced trainer and E.44 and 45 fighters. First to be built in numbers was E.114 2-seat ultralight, but few were built of twin-pusher 4-seat E.210, single-tractor E.214 and E.241 biplane trainer. On German occupation 1939 company became Böhmische-Mährische Maschinenfabriken AG on general war production. Factory re-established 1947 as Závody Letecké Praga, producing small number of E.210/211 and 114, and Doris B flat-6 engine.