Due to the technological development the scope of State aircraft application has significantly expanded. As a result there is a need to study the current international legal approach to the definition of “State aircraft” with respect to its applicability to existing relations. Furthermore, the distinction between state and civil aviation is a critical issue in determining the scope of international air law instruments. The authors analyze different approaches to the definition of “State aircraft” at the universal, regional and bilateral level. The study has revealed that there is no holistic understanding of the concept of “state aircraft” in current international law, which has a negative impact on the international legal regulation. The authors conclude that it is advisable to revise the definition of “state aircraft” at the universal level, which should serve as an impetus for further unification of the legal regulation. The authors propose to expand t his legal category beyond the provisions of the 1944 Chicago Convention. This paper argues that it would be in the interests of modern aviation and would address existing and potential legal problems.