One flies Aussie songstress that is off visiting Channel Island (7)
I believe the answer is:
skylark
'one flies aussie songstress that is off visiting' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'channel island' is the wordplay.
'channel' becomes 'sky' (TV company).
'island' becomes 'lark' (I can't explain this - if you can you should believe this answer much more).
'sky'+'lark'='SKYLARK'
Can you help me to learn more?
(Other definitions for skylark that I've seen before include "Common songbird" , "Flyer" , "Bird (of 23?)" , "Bird that sings aloft" , "Ode to a ... (Shelley)" .)