Discarded material from planes in the morning (6)
I believe the answer is:
jetsam
'discarded material' is the definition.
'planes in the morning' is the wordplay.
'planes' becomes 'jets' (jet is a kind of plane).
'in the morning' becomes 'am' (AM on a clock).
'jets'+'am'='JETSAM'
'from' is the link.
(Other definitions for jetsam that I've seen before include "Goods thrown overboard and washed up on shore" , "Stuff cast overboard" , "lost cargo" , "Goods jettisoned from a ship and washed up on shore" , "Flotsam and --" .)