A plane is out of the way (5)
I believe the answer is:
aside
'is out of the way' is the definition.
(I've seen this before)
'a plane' is the wordplay.
'plane' becomes 'side' (I can't explain this - if you can you should believe this answer much more).
'a'+'side'='ASIDE'
Can you help me to learn more?
(Other definitions for aside that I've seen before include "Apart; incidental remark" , "(Pushed) out of the way" , "Actor's covert line" , "Remark by an actor, directly to audience say" , "Where one's taken for intimacy" .)