Scheme for alien on Earth, say (6)
I believe the answer is:
planet
'earth say' is the definition.
(Earth is an example)
'scheme for alien' is the wordplay.
'scheme' becomes 'plan' (I've seen this before).
'for' says to put letters next to each other.
'alien' becomes 'et' (extra terrestrial).
'plan'+'et'='PLANET'
'on' acts as a link.
(Other definitions for planet that I've seen before include "Celestial body orbiting around a star" , "Earth, for instance" , "Large body orbiting sun" , "Satellite of a sun" , "Mars or Uranus" .)