The purpose of this article is to highlight the legal implications of the lack of uniform practice of states with regard to defining the status of aircraft and flight, which determine the application of relevant aviation regulations in ensuring the safety of air navigation. The article analyses the most important conventions of international aviation law and discusses cases involving the same aircraft, to which, depending on the circumstances and the qualification of the aircraft, the relevant laws will apply. The same aircraft may in a certain situation be considered as either civil or state aircraft, and consequently other aviation regulations may find application to the operation performed by it. The author has attempted to analyse the provisions of international law in terms of legal gaps related to the application of the relevant legal regime in the context of the aircraft and the flight associated with it.