Aviation hero (3)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">aviation hero</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ace that I've seen before include "Dab hand" , "Tennis serve that the opponent can't reach" , "Entertain" , "Adept" , "fighter pilot" .)