Company car? (3-6)
I believe the answer is:
two-seater
'company car?' is the definition.
'two seater' can be an answer for 'car?' (I've seen this before). I am unsure of the 'company' bit.
'company car?' is the wordplay.
'company' becomes 'two' (I've seen this in another clue).
'car?' becomes 'seater' (I am not sure about this - if you are sure you should believe this answer much more).
'two'+'seater'='TWO-SEATER'
(Other definitions for two-seater that I've seen before include "Small car" , "Sports car" .)