Communist spy's early flight (3-3)
I believe the answer is:
red-eye
'early flight' is the definition.
(flight early in the morning)
'communist spy's' is the wordplay.
'communist' becomes 'red' (red can informally mean communist).
'spy' becomes 'eye' (both can mean to see).
'red'+'eye'='RED-EYE'
(Other definitions for red-eye that I've seen before include "Poor whiskey - overnight flight" , "Poor quality, coarse powerful whiskey" .)