Get rid of plane - it returned with boy (8)
I believe the answer is:
jettison
'get rid of' is the definition.
(I've seen this before)
'plane it returned with boy' is the wordplay.
'plane' becomes 'jet' (jet plane).
'returned' says the letters should be written backwards.
'with' says to put letters next to each other.
'boy' becomes 'son' (male child).
'it' reversed gives 'ti'.
'jet'+'ti'+'son'='JETTISON'
(Other definitions for jettison that I've seen before include "Abandon or throw overboard" , "Remove" , "Ditch (cargo)" , "'Throw away, cast overboard (8)'" , "Chuck overboard" .)