Russian invasion of Ukraine on 24th February 2022 leds to the restriction of air traffic in Ukrainian and Russian air spaces due to the military activity and war-related sanctions. Airspace closures have forced airlines to take detours and seek alternative routes. All these causes considerable increasing of flight time on routes connecting Europe and Asia, North America and Asia and North America and Middle East. In turns longer travel times lead to the increasing of aircrafts’ fuel burn, which causes higher airlines operating costs and CO2 emissions. This paper assesses the impact of the Russian invasion of Ukraine on the global air transportation ecosystem on the example of three European airlines, i.e. Finnair, LOT Poilish and Lufthansa Airlines, analysing their most popular routes between Europe and Asia before and after flight restrictions. Performed analysis shows increasing of the airlines operations costs and CO2 emissions from 18% to 40% on the certain routes after closure of air spaces. This research also contains a forecast of global aviation CO2 emissions for the next five years under the two different scenarios of military conflict development on the territory of Ukraine, constructed with the help SARIMA Model.