TY JOUR TI Financial results of Russian civil aviation enterprises KW airline KW financial balance of the air transport organization KW income and expenses KW economic efficiency KW state aid KW Russian aviation KW aviation economics KW financial stability of the enterprise JO JOURNAL OF MONETARY ECONOMICS AND MANAGEMENT AU Sushko, O.P. AU Burdyuzha, A.D. PY 2026 IS 0 PB ITBO University