A gaggle of high-fliers (5)
I believe the answer is:
skein
'a gaggle' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for skein that I've seen before include "Coil of wool - flock of geese" , "Loosely coiled length of thread" , "Loosely coiled bundle of wool" , "Loose bundle of yarn" , "Flock of flying geese" .)