In aviation and in space, a drone refers to an unmanned aircraft or spaceship. Another term for this is an unmanned aerial vehicle or UAV. An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. Unmanned aerial vehicles were originally developed throughout the 20th century for military missions that were too boring, dirty, or dangerous for humans and, by the 21st century, they had become essential assets for most armies.
As control technologies improved and costs fell, their use expanded to many non-military applications. These include aerial photography, precision agriculture, wildfire monitoring, river monitoring, environmental monitoring, police surveillance and surveillance, infrastructure inspections, smuggling, product delivery, entertainment, and drone racing.