Warplane (6)
I believe the answer is:
bomber
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">warplane</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for bomber that I've seen before include "Aircraft designed to drop high explosives" , "Military aircraft" , "military plane" , "Zip-up garment elasticated at the waist and cuffs" , "terrorist" .)