The article provides legal analysis on co-dependence between nautical and aviation regulations in international law and practice. The study focuses on overflight rights with respect to civil and military aviation across distinct types of waters as defined by the United Nations Convention on the Law of the Sea (UNCLOS 1982) where the Author differentiates the common legal standard from particular legal regulations giving rise to divergent practices of some countries. The article touches also a number of issues relating to maritime security (including the threat of piracy) and to environmental protection in the context of regulation and practice of airborne activities carried out by states’ authorities and services.