Flyer's transport almost late (7)
I believe the answer is:
bustard
'flyer's' is the definition.
(I've seen this before)
'transport almost late' is the wordplay.
'transport' becomes 'bus' (busing is a kind of transporting).
'almost' means to remove the last letter (most of the word but not all of it).
'late' becomes 'tardy' (synonyms).
'tardy' with its last letter removed is 'tard'.
'bus'+'tard'='BUSTARD'
(Other definitions for bustard that I've seen before include "flyer" , "Long-legged, heavy-bodied bird" , "Bad rust (anag.)" , "Large heavy bird" , "See large bird" .)