Flier is power fanatic (6)
I believe the answer is:
plover
'flier' is the definition.
(plover is a kind of birdanimal)
'power fanatic' is the wordplay.
I cannot quite see how this works, but
'power' could be 'p' (symbol in physics) and 'p' is found in the answer.
The remaining letters 'lover' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'is' acts as a link.
Can you help me to learn more?
(Other definitions for plover that I've seen before include "Short-billed shore bird" , "Lapwing, for example" , "Kind of wading bird" , "Lapwing-like bird" , "Wader" .)