Unmanned aircraft systems have evolved rapidly in recent years. This evolution involves the development of UAS applications that many experts did not anticipate ever occurring. This evolution has left regulatory bodies with a wide gap between the technology available and the regulation, procedures, and documentation to regulate and manage it. The Federal Aviation Administration is the United States’ lead government organization in the effort to integrate this technology into the National Airspace System. Many government and industry organizations are working with the FAA on this task, which includes the execution of research and development projects. The FAA and its partners are also working with international governments and organizations to harmonize global requirements. Significant progress has been made toward this integration, but there is an extensive amount of research and development that must occur to reach full integration.