Inside of barn, turn left to see fabulous flier (9)
I believe the answer is:
archangel
'fabulous flier' is the definition.
'archangel' can be an answer for 'flier' (I have seen 'celestial flier' mean 'archangel' so perhaps 'flier' could also mean 'archangel'). I'm unsure of the 'fabulous' bit.
'inside of barn turn left' is the wordplay.
'inside of' means to look at the middle letters.
'turn' becomes 'change' (I can't explain this - if you can you should give a lot more credence to this answer).
'left' becomes 'l' (common abbreviation).
The middle of 'barn' is 'ar'.
'ar'+'change'+'l'='ARCHANGEL'
'to see' acts as a link.
Can you help me to learn more?
(Other definitions for archangel that I've seen before include "Port in northern Russia, or senior heavenly messenger" , "Senior spirit; Russian port" , "What we call a port" , "The head celestial messenger" , "one coming from above with message maybe" .)