Despite the obvious shortcomings, Soviet airmen believed that the air operations at Moscow and during the winter offensive that followed had confirmed the basic tenets of Soviet air doctrine . Air power had been massed on the major attack zones in an offensive. Air reserves were maneuvered and extensively used. VVS commanders and staffs had worked closely with the ground forces to achieve close co-ordination of Frontal Aviation and ground units in combined-arms operations. Both DBA and Istrebitel'naia Aviatsiia/Protivovozdushnaia Oborona (IA/ PVO) (Fighter Aviation/Air Defense) units had been used in co-operation with Frontal Aviation.