Aircraft means any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface;
Unmanned aircraft means any aircraft operating or designed to operate autonomously or to be piloted remotely without a pilot on board;
Public aircraft means an aircraft used exclusively in the service of any government or of any political subdivision thereof, including the government of any state, territory, or possession of the United States, or the District of Columbia, but not including any government-owned aircraft engaged in carrying persons or property for commercial purposes.
Unmanned aircraft system means an unmanned aircraft and associated elements, including communication links and components that control the unmanned aircraft that are required for the pilot in command to operate safely and efficiently in the national airspace system.