A plane maybe circling popular race venue (7)
I believe the answer is:
aintree
'race venue' is the definition.
I know nothing about this answer so I can't tell whether this works.
'a plane maybe circling popular' is the wordplay.
'plane maybe' becomes 'tree' (plane is a type of tree).
'circling' indicates putting letters inside (circling can mean going around or containing).
'popular' becomes 'in' (something that's 'in' is fashionable).
'a'+'tree'='atree'
'atree' enclosing 'in' is 'AINTREE'.
Can you help me to learn more?
(Other definitions for aintree that I've seen before include "Home of the Grand National" , "Grand National course" , "Venue of the Grand National race" , "National racecourse" , "Merseyside racecourse" .)