Fliers postmaster general's carrying around (6)
I believe the answer is:
egrets
'fliers' is the definition.
(egret is a kind of bird)
'postmaster general's carrying around' is the wordplay.
'carrying' indicates a hidden word.
'around' says the letters should be written backwards.
'sterge' is hidden in the letters of 'postmaster generals'.
'sterge' written backwards gives 'EGRETS'.
(Other definitions for egrets that I've seen before include "Kind of herons with long white feathers" , "White wading birds" , "creatures" , "Greets like certain herons" , "Fliers" .)