Sentence:  In his submission to the UN, [Christof] Heyns points to the experience of drones. Unmanned <WSD>aerial</WSD> vehicles were intended initially only for surveillance, and their use for offensive purposes was prohibited, yet once strategists realised their perceived advantages as a means of carrying out targeted killings, all objections were swept out of the way. 
Meaning of the word marked with <WSD> tags:  Pertaining to a vehicle which travels through the air; airborne; relating to or conducted by means of aircraft. (from 17th c.)