Display skill in flying machines (8)
I believe the answer is:
aircraft
'flying machines' is the definition.
(I've seen this before)
'display skill' is the wordplay.
'display' becomes 'air' (air can mean to display or show something).
'skill' becomes 'craft' (craft is a kind of skill).
'air'+'craft'='AIRCRAFT'
'in' acts as a link.
(Other definitions for aircraft that I've seen before include "Flying machines" , "Eg, plane, helicopter, etc" , "Vehicle that can fly" , "Flying vehicle" , "High-flier" .)