The rapid increase and popularity of Unmanned Aircraft Systems (UAS) in civil usage around the world is due to their versatility. With advancement in technology across the globe, there are UAS of different sizes and capabilities in the market. It is imperative to note that the use and operation of UAS have numerous merits and equally, potentially poses serious risks to aviation safety, unlawful interference with States’ security as well as invasion of the privacy of persons. This reality poses a challenge to integration of UAS into the civil airspaces of different States. Accordingly, the international community developed the Chicago Convention that provides the principal framework to address the threefold concerns. At the international level, however, there is lack of a unified system of regulation of UAS. Consequently, the Chicago Convention requires States to develop national institutions and legal frameworks to not only effectively address these concerns, but also create a delicate balance between national security and right to privacy. This thesis evaluates how the legal, institutional and policy frameworks for UAS in the US, South Africa and Kenya have addressed the current needs and challenges in operation and integrating them into regulatory frameworks for civil aviation. It follows that the three States have developed constitutional frameworks, legislation, regulations, policies and strategic plans as they seek to address the challenges that emanate from integrating UAS into the civil aviation airspace. This encompasses ineffective enforcement mechanism of regulations. The thesis maps out experiences of integration in the three countries, emanating from research goals including investigating the extent to which existing international regulatory frameworks address the threefold concerns. The study establishes that the common thread running through UAS regulation is each country’s unique issues and paths to integration. Additionally, that the approach for integration of UAS into civil aviation needs be gradual and pragmatic. For this reason, this thesis recommends the development of institutional capacity, coordination and funding, and increase in regional efforts to revamp UAS integration efforts into civil aviation. / Public, Constitutional, and International Law / LL. D. (Public, Constitutional and International Law)