What fighter may carry out through following cunning (5)
I believe the answer is:
flyby
'what fighter may carry out' is the definition.
(a fighter jet might carry out a flyby)
'through following cunning' is the wordplay.
'through' becomes 'by'.
'following' means one lot of letters go next to another.
'cunning' becomes 'fly' (fly can mean skilful or sharp).
'by' put after 'fly' is 'FLYBY'.
(Other definitions for flyby that I've seen before include "Low pass at air display" , "Part of probe's track closest to the observed planet" .)