Ditched, having flown over island — no point coming back (10)
I believe the answer is:
jettisoned
'ditched' is the definition.
(I've seen this before)
'flown over island no point coming back' is the wordplay.
'flown' becomes 'jetted' (jetting is a kind of flying).
'over' means one lot of letters goes inside another.
'island' becomes 'i'.
'no point' becomes 'nos' (I can't explain this - if you can you should give a lot more credence to this answer).
'coming back' says the letters should be written backwards.
'nos' in reverse letter order is 'son'.
'i'+'son'='ison'
'jetted' placed around 'ison' is 'JETTISONED'.
'having' is the link.
(Other definitions for jettisoned that I've seen before include "Thrown away" , "Threw away" , "Ditched" , "thrown out of plane" , "dumped" .)