Argue about Liberal left probing Knock airport's information pack (6,4)
I believe the answer is:
flight plan
'information pack' is the definition.
The definition suggests a singular noun which matches the answer.
'argue about liberal left probing knock airport's' is the wordplay.
'argue' becomes 'fight' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'liberal' becomes 'l' (abbreviation).
'left probing knock airport's' becomes 'plan' (I am not sure about this - if you are sure you should believe this answer much more).
'fight' placed around 'l' is 'flight'.
'flight'+'plan'='FLIGHT PLAN'
Can you help me to learn more?
(Other definitions for flight plan that I've seen before include "Aircraft's filed route" , "Proposed route for aircraft" .)