Initially, the English word "drone" meant both an insect and a sound. It was not until the outbreak of World War II that it began to take on another meaning. At that time, American artillery apprentices used the expression "target drones" to designate the small remotely controlled planes at which they aimed in training. The metaphor did not refer solely to the size of those machines or the brm-brm of their motors. Drones are male bees, without stingers, and eventually the other bees kill them. Classical tradition regarded them as emblems of all that is nongenuine and dispensable. That was precisely what a target drone was: just a dummy, made to be shot down.
However, it was a long time before drones were to be seen cruising above battlefields. To be sure, the idea dates back quite a while: there were the Curtiss-Sperry aerial torpedo and the Kettering Bug at the end of World War I, and then the Nazi V-1s and V-2s unleashed on London in 1944. But those old flying torpedoes may be considered more as the ancestors of cruise missiles than as those of present-day drones. The essential difference lies in the fact that while the former can be used only once, the latter are reusable. The drone is not a projectile, but a projectile-carrying machine.
It was during the Vietnam War that the U.S. Air Force, to counteract the Soviet surface-to-air missiles that had inflicted heavy casualties on it, invested in reconnaissance drones nicknamed "Lightning Bugs," produced by Ryan Aeronautical. An American official explained that "these RPVs [remotely piloted vehicles] could help prevent aircrews from becoming casualties or prisoners... With RPVs, survival is not the driving factor."
Comment: What most of this military jargon is really talking about, especially predators stalking prey and manhunting as a preventative measure, is militaries, specifically the U.S. military, no longer engaging with modern armies but with civilians, occupants of the countries they are taking over. These executions are not about stopping an army from harming the U.S., it's about terrorizing people into giving in to the U.S. Empire's control. The U.S. is not engaged in a War on Terror, it's in a War of Terror.