Fly round a northern German city (7)
I believe the answer is:
hanover
'german city' is the definition.
(I've seen this before)
'fly round a northern' is the wordplay.
'fly' becomes 'hover' (hovering is a kind of flying**).
'round' is an insertion indicator.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'a'+'n'='an'
'hover' enclosing 'an' is 'HANOVER'.
(Other definitions for hanover that I've seen before include "10 [HOUSE]" , "Royal house from George I to Victoria" , "Royal house from 1727" , "German town, and royal house" , "British dynasty" .)