Parrot madly circles one transport hub (7)
I believe the answer is:
airport
'transport hub' is the definition.
(I've seen this before)
'parrot madly circles one' is the wordplay.
'madly' is an anagram indicator.
'circles' indicates putting letters inside.
'one' becomes 'I' (Roman numeral).
'parrot' is an anagram of 'arport'.
'arport' placed around 'i' is 'AIRPORT'.
(Other definitions for airport that I've seen before include "Place for planes" , "Fliers' terminus" , "Place from which to fly" , "John Lennon, say" , "Novel by Arthur Hailey" .)