Top pilots (4)
I believe the answer is:
aces
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">top pilots</span>' is the definition.<br/ ><span class="explanation-format__explanation">(ace can mean a fighter pilot)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for aces that I've seen before include "passes with flying colours in US" , "Flying war heroes" , "Winning serves" , "Unreturnable services" , "excellent service" .)