Aircraft’s unfinished chart (4)
I believe the answer is:
plan
'chart' is the definition.
(I know that chart is a more specific form of the action plan)
'aircraft's unfinished' is the wordplay.
'aircraft' becomes 'plane' (plane is a kind of aircraft).
'unfinished' means to remove the last letter.
'plane' with its final letter removed is 'PLAN'.
(Other definitions for plan that I've seen before include "Road map" , "Intention or decision about what one is going to do" , "Large-scale map" , "Scale drawing of a structure" , "Diagram; design" .)