Fly in jet set section (6)
I believe the answer is:
tsetse
'fly' is the definition.
(tsetse is a kind of fly)
'in jet set section' is the wordplay.
'in' says the answer is hidden in the clue.
'TSETSE' is hidden within 'jet set section'.
(Other definitions for tsetse that I've seen before include "African transmitter" , "cause of sleepiness?" , "flies" , "fly across Africa" , "source of sleeping sickness" .)