Delivery involving a lengthy air journey (4,3)
I believe the answer is:
long hop
'delivery' is the definition.
Both the answer and definition are singular nouns.
Perhaps they are linked in a way I don't understand?
'a lengthy air journey' is the wordplay.
'a lengthy' becomes 'long' (I've seen this in another clue).
'air journey' becomes 'hop' (as in a short hop, a short journey. I am not sure about the 'air' bit.).
'long'+'hop'='LONG HOP'
'involving' is the link.
Can you help me to learn more?
(Other definitions for long hop that I've seen before include "short ball" , "A friendly ball" , "Lengthy dance" .)