One dumped on old aircraft — time to see another world (9)
I believe the answer is:
'another world' is the definition.
(planet outside our solar system)
'one dumped on old aircraft time' is the wordplay.
'one dumped' becomes 'ex' (a former partner, someone who was dumped).
'on' is a charade indicator (letters next to each other).
'old' becomes 'o' (abbreviation).
'aircraft' becomes 'plane' (plane is a kind of aircraft).
'time' becomes 't' (abbreviation).
'to see' is the link.
(Other definitions for exoplanet that I've seen before include "where no human has ever been" , "distant world" .)