In pilgrims’ airport, drink is cheap (9)
I believe the answer is:
knockdown
'cheap' is the definition.
(I've seen this before)
'in pilgrims' airport drink' is the wordplay.
'in pilgrims' airport' becomes 'knock' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'drink' becomes 'down' (downing is a kind of drinking).
'knock'+'down'='KNOCKDOWN'
'is' acts as a link.
(Other definitions for knockdown that I've seen before include "Fell" , "very low" , "Cheap - floor" .)