The flighty fellow's collecting Maria at mid-morning (6)
I believe the answer is:
airman
'the flighty fellow's collecting' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'maria at mid-morning' is the wordplay.
I cannot quite see how this works, but
an anagram of 'maria' is 'airma' which is located in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for airman that I've seen before include "Aviator" , "He flies" , "Pilot" , "crew member" , "Flier" .)