Unmanned Aerial Vehicles (UAVs) like drones and quadcopters have revolutionized flight.They help humans to take to the air in new, profound ways. The military use of larger size UAVs hasgrown because of their ability to operate in dangerous locations while keeping their human operators at asafedistance.HerequadcopterasasmallUAVisdiscussed.Itistheunmannedairvehiclesandplayingapredominantroleindiffe rentareaslikesurveillance,militaryoperations,firesensing,trafficcontrolandcommercial and industrial applications.