Sperrle was assisted by the Oberkommando der Luftwaffe (OKL—High Command of the Air Force). Staff officers were trained to solve operational level problems and the OKL's reluctance to micromanage gave Sperrle and Richthofen a free hand to devise solutions to tactical and operational problems. An important step was the development of ground-air communication, via the use of frontline signals posts which were in contact with army and airbases simultaneously. Information telephoned to airbases was relayed rapidly by radio to aircraft in flight. This innovation was put into practice during the conflict.