Avail yourself of the plane coming back, too... (5)
I believe the answer is:
level
'avail' is the definition.
The definition and answer can be both human attributes as well as being singular nouns.
Maybe there's an association between them I don't understand?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for level that I've seen before include "Floor; horizontal" , "Palindromically smooth" , "Neither winning, nor losing" , "Storey - stage" , "Equal; flat" .)