Newly recruited flier, that is (6)
I believe the answer is:
rookie
'newly recruited flier that is' is the definition.
I can't tell whether this definition defines the answer.
'flier that is' is the wordplay.
'flier' becomes 'rook' (rook is a kind of birdanimal).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'rook'+'ie'='ROOKIE'
Can you help me to learn more?
(Other definitions for rookie that I've seen before include "Novice" , "new team member" , "Beginner as in the army" , "untrained soldier" , "Slang for a new recruit" .)