The paper deals with the use of unmanned aircraft of the American national security policy. It examines the history of unmanned aviation, its military use, and cost- efficiency. It then examines the main obstacles and problems with their use in national security that this technology meets and will meet in the future after a higher level of autonomy is developed. These problems involve legal issues, international and domestic American law, the issue of civilian casualties, the role of the media, and public opinion. The final chapter focuses on the problems of technical, strategic and operational issues. In this section the research paper comes to the first conclusion which claims that the introduction of more autonomous systems to war will radically change its structure and, consequently, standard procedures and strategies. Case studies are included to illustrate how successful the drone strategy is applied in the five countries where the United States leads a war on terror. The research using the theory of the revolution in military affairs concludes that these UAVs pose the greatest challenge in history and it goes well beyond military matters. UAVs in national security affect the understanding of the basic principles of war in relation to the concepts of warrior ethos and just war.