Alien departing from gate in Scottish airport (4)
I believe the answer is:
wick
'scottish airport' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'alien departing from gate' is the wordplay.
'alien' becomes 'et' (extra terrestrial).
'departing from' suggests deleting specific letters.
'gate' becomes 'wicket gate' (wicket gate is a kind of gate).
'wicket' with 'et' taken away is 'WICK'.
'in' is the link.
Can you help me to learn more?
(Other definitions for wick that I've seen before include "Length of thread in centre of candle" , "Candle fibre" , "Beginners" , "Highland burgh" , "Caithness seaport" .)