In flight, bat is not a plant-fancier (8)
I believe the answer is:
botanist
'a plant-fancier' is the definition.
I can't tell whether this definition defines the answer.
'in flight bat is not' is the wordplay.
'in flight' indicates anagramming the letters (the letters fly around).
'bat'+'is'+'not'='batisnot'
'batisnot' with letters rearranged gives 'BOTANIST'.
Can you help me to learn more?
(Other definitions for botanist that I've seen before include "investigating bloomers, for example?" , "Expert in the scientific study of plants" , "To sit ban out for expert in study of plants" , "Plant scientist" , "Studier of plants" .)