Drunk husband drinking more getting half-cut in plane (6)
I believe the answer is:
smooth
'plane' is the definition.
(smooth plane is a kind of plane)
'drunk husband drinking more getting half-cut' is the wordplay.
'drunk' becomes 'sot' (sot can mean a drunken person).
'husband' becomes 'h' (abbreviation).
'drinking' indicates putting letters inside (inserted letters are consumed or drunk).
'getting half cut' means to take half the letters.
'sot'+'h'='soth'
'more' cut in half is 'mo'.
'soth' placed around 'mo' is 'SMOOTH'.
'in' acts as a link.
(Other definitions for smooth that I've seen before include "Even; without jerks" , "Still" , "Easy" , "Level; suave" , "Hairless" .)