Flyer’s attempt at test taking hours (4,4)
I believe the answer is:
'flyer's' is the definition.
'attempt at test taking hours' is the wordplay.
'attempt' becomes 'go' (go is a kind of attempt).
'test' becomes 'MOT' (as in an MOT test for a vehicle).
'taking' says to put letters next to each other.
'hours' becomes 'h'.
(Other definitions for goat moth that I've seen before include "Creature" , "One flying" .)