More than three dozen countries in the World of Drones database have armed drones, but not all of them produced their UCAVs at home. More than 100 countries and non-state groups have drones, and many actors have access to armed drones. In fact, as Paul Scharre, director of studies at the Center for New American Security, says, it seems that the proliferation of these systems will continue. The record for the distance of a UAV (built of balsa wood and mylar skin) across the North Atlantic Ocean is held by a model of a gasoline-powered aircraft or UAV.
Unmanned aerial vehicles can be designed in different configurations than manned aircraft, both because they do not need a cockpit or windows and because it is not necessary to optimize them for people's comfort, although some unmanned aerial vehicles are adapted to piloted models or are designed for piloted modes as an option. Military unmanned aerial systems (UAS) classify unmanned aerial vehicles based on the weight, maximum altitude, and speed of the unmanned aerial vehicle component.