Airport building (8)
I believe the answer is:
terminal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">airport building</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for terminal that I've seen before include "Occurring at the end" , "part of Heathrow?" , "Fatal - tram line (anag)" , "Electricity connection point" , "At the end, final" .)