Scrap metal plating thus put on aircraft (8)
I believe the answer is:
jettison
'scrap' is the definition.
(thesaurus)
'metal plating thus put on aircraft' is the wordplay.
'metal' becomes 'tin' (tin is a kind of metal**).
'plating' is an insertion indicator (I've seen this in other clues).
'thus' becomes 'so' ('so' can be a synonym of 'thus').
'put on' is a charade indicator (letters next to each other).
'aircraft' becomes 'jet' (jet is a kind of aircraft).
'tin' going around 'so' is 'tison'.
'tison' put after 'jet' is 'JETTISON'.
(Other definitions for jettison that I've seen before include "Throw overboard or discard unwanted material" , "Reject" , "Throw goods overboard, or discard what is unwanted" , "Throw away (from ship or aeroplane?)" , "Deliberately dump overboard" .)