Emergency flight served by express elevator (7)
I believe the answer is:
airlift
'emergency flight' is the definition.
'airlift' can be an answer for 'flight' (thesaurus). I am unsure of the 'emergency' bit.
'by express elevator' is the wordplay.
'by' means one lot of letters go next to another.
'express' becomes 'air' (I've seen this before).
'elevator' becomes 'lift' (synonyms).
'air' next to 'lift' is 'AIRLIFT'.
'served' acts as a link.
Can you help me to learn more?
(Other definitions for airlift that I've seen before include "(Emergency) flight" , "Emergency supply by plane" , "Berlin relief, 1948" , "Transportation of goods to inaccessible place" , "means of escape" .)