Take flight in retirement (7)
I believe the answer is:
retreat
This clue is a double definition.
'take flight' is the first definition.
(thesaurus)
'retirement' is the second definition.
('retreat' can be a synonym of 'retirement')
'in' is the link.
(Other definitions for retreat that I've seen before include "care home" , "unhappy manoeuvre" , "Tree rat (anag)" , "Give ground" , "Monastery - bugle call" .)