The basic purpose of the article is considering problems related to ensuring the required capacity of Lithuanian airspace and organising the provision of air traffic services in the most efficient way. The paper presents the results of analysis and experimental research on several scenarios of Lithuanian airspace models that are the most appropriate from the point of view of air traffic control. To allow for a realistic comparison between the scenarios and traffic samples, the current route network, a real traffic sample and the existing traffic dynamics have been used. Furthermore, all other related aspects such as flight level occupancy, flight time, aircraft type and traffic flows have been taken into consideration. The results of analysis will form a basis for ensuring the required capacity of Lithuanian airspace.