The Aero A.204 was a Czechoslovakian airliner that flew in prototype form in 1936. It was developed specifically for ČSA but much to Aero's surprise and disappointment the national airline selected a British product instead the Airspeed Envoy. Unable to find a customer Aero began to develop a military version instead as the A.304. Whilst Czechoslovakia was under occupation by Nazi Germany Aero manufactured the Siebel Si 204 under licence.
Made by Aero Vodochody.