Cladding of flying saucer - surely it's missing? (6)
I believe the answer is:
facing
'cladding' is the definition.
('facing' can be a synonym of 'cladding')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for facing that I've seen before include "on the opposite side" , "Outer layer covering the surface of a wall" , "Revetment" , "Confronting and dealing with" , "Turning towards, perhaps the enemy" .)