He gives okay to pilots (5)
I believe the answer is:
roger
'he' is the definition.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for roger that I've seen before include "Received (in radio comms)" , "Sir - de Coverley, English country dance" , "that's clear" , "Message received; name" , "Boy's name - message understood" .)