Air foul footwear after short time (3,3,3)
I believe the answer is:
tea for two
'air' is the definition.
(I've seen this before)
'foul footwear after short time' is the wordplay.
'foul' indicates anagramming the letters.
'after' says to put letters next to each other.
'short time' becomes 't' (abbreviation for time).
'footwear' with letters rearranged gives 'eafortwo'.
'eafortwo' put after 't' is 'TEA FOR TWO'.
(Other definitions for tea for two that I've seen before include "Popular 1925 song (for afternoon drinking companions?)" , "Air" , "Song from musical No, No, Nanette" , "Musical number" .)