But this officer cannot necessarily fly (5)
I believe the answer is:
pilot
'fly' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for pilot that I've seen before include "Test or trial (project or programme)" , "Navigate" , "Lead" , "One who brings a vessel into port" , "Guide - flier" .)