London airport (8)
I believe the answer is:
heathrow
'london airport' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for heathrow that I've seen before include "site for airport" , "lots of movement through the air here" , "London's busiest airport" , "our counterpart of Charles de Gaulle" , "London airport" .)