Cricket game: plan to include one high-flier (4,5)
I believe the answer is:
test pilot
'flier' is the definition.
(I know that test pilot is a type of aircraft pilot)
'cricket game plan to include one' is the wordplay.
'cricket game' becomes 'test' (I can't justify this - if you can you should give a lot more credence to this answer).
'plan' becomes 'plot' (plot is a kind of plan).
'to include' indicates putting letters inside.
'one' becomes 'I' (Roman numeral).
'plot' enclosing 'i' is 'pilot'.
'test'+'pilot'='TEST-PILOT'
'high' acts as a link.
This may not be correct. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for test pilot that I've seen before include "Experimental flyer" , "one examining details of flight, spin, etc" , "highflying expert" , "one occupying 21 [COCKPIT]" , "Stop title (anag.)" .)