Flyer gets sum wrong in puzzle (6)
I believe the answer is:
bemuse
'puzzle' is the definition.
(I've seen this before)
'flyer gets sum wrong' is the wordplay.
'flyer' becomes 'emu' (emu is a type of bird).
'gets' is an insertion indicator.
'sum wrong' becomes 'bse' (I can't justify this - if you can you should give a lot more credence to this answer).
'emu' going into 'bse' is 'BEMUSE'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for bemuse that I've seen before include "Perplex" , "Fox" , "Bewilder or baffle" , "Confound" , "Confuse, bewilder" .)