Counter drones flying over centre of airport (7)
I believe the answer is:
respond
'counter' is the definition.
(thesaurus)
'drones flying over centre of airport' is the wordplay.
'flying' indicates anagramming the letters.
'over' means one lot of letters goes inside another.
'centre of' indicates the central letters.
The centre of 'airport' is 'p'.
'drones' with letters rearranged gives 'resond'.
'resond' placed around 'p' is 'RESPOND'.
(Other definitions for respond that I've seen before include "Write back" , "React (positively) to a stimulus or treatment" , "Answer back" , "Answer or react" , "Reply - react" .)