Pilotless aircraft (5)
I believe the answer is:
drone
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pilotless aircraft</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for drone that I've seen before include "Talk boringly; male bee" , "Idle type" , "person averse to work" , "Idle person; bee" , "Idler like male bee" .)