The book is devoted to the analysis of the combat use of Soviet aviation in the war with Finland of 1939-1940. The physical, geographical and climatic conditions of the theater of military operations, the state and grouping of Soviet and Finnish troops are considered as factors that influenced the creation and build-up of the aviation group of the Soviet Air Force, planning of combat operations, control of the group, and interaction with other branches of the military. The features of the basing and comprehensive supply of Soviet aviation in the combat area are considered. The work shows the difficulties of performing tasks in conditions of directionless terrain and counteraction to enemy aviation and anti-aircraft weapons.