A couple on aircraft parking area (5)
I believe the answer is:
apron
'aircraft parking area' is the definition.
(I've seen this before)
'a couple on' is the wordplay.
'couple' becomes 'pr'.
'a'+'pr'+'on'='APRON'
(Other definitions for apron that I've seen before include "Kitchen garment or part of airfield" , "Domestic protection" , "item of protective clothing" , "Protective garment worn at front" , "stage perhaps" .)