A Republican with fortified wine collects one from Gatwick, say (7)
I believe the answer is:
airport
'gatwick say' is the definition.
(I know that Gatwick Airport is a international airport)
'a republican with fortified wine collects one' is the wordplay.
'republican' becomes 'r' (abbreviation).
'with' means one lot of letters go next to another.
'fortified wine' becomes 'port' (port is a kind of fortified wine).
'collects' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
'a'+'r'+'port'='arport'
'arport' placed around 'i' is 'AIRPORT'.
'from' acts as a link.
(Other definitions for airport that I've seen before include "Centre for planes coming and going" , "Aviation centre" , "John Lennon, say" , "... [GAULLISM] its founder perhaps" , "plane where it lands" .)