Dutch town flown over last night (5)
I believe the answer is:
delft
'dutch town' is the definition.
(I've seen this before)
'flown over last night' is the wordplay.
'flown' becomes 'fled' ('flee' can be a synonym of 'fly').
'over' is a reversal indicator.
'last' indicates one should take the final letters.
The final letter of 'night' is 't'.
'fled' in reverse letter order is 'delf'.
'delf'+'t'='DELFT'
(Other definitions for delft that I've seen before include "Netherlands town - glazed earthenware" , "Dutch blue and white ware" , "crockery pieces" , "Glazed earthenware, usually white with blue decoration" , "Dutch pottery town" .)