I. Introduction
Today a civil aviation my be refered to one of the most developing transportation systems. Many advantages of this transport stimulate the continuous growth of the airline industry. Aviation equipment that is used today supports direct air connection between any two airports global. The continuous growth of air transportation volume leads to an increasing number of airplanes that simultaneously use airspace. However, airspace has a limited capacity due to requirements from flight safety side to ensure safe services. The transportation crisis caused by COVID-19 and travel restrictions related to them slowed down the pace of air transportation development over the last few years. Today European transportation developing rapidly and has reached more than 70% of pre-pandemic volume.