Conclusive statement about Irish flyers (6)
I believe the answer is:
airmen
'flyers' is the definition.
('airman' can be a synonym of 'flyer')
'conclusive statement about irish' is the wordplay.
'conclusive statement' becomes 'amen' (I have seen 'statement of affirmation' mean 'amen' so perhaps 'statement' could also mean 'amen'. I am not sure about the 'conclusive' bit.**).
'about' indicates putting letters inside.
'irish' becomes 'ir' (abbreviation).
'amen' enclosing 'ir' is 'AIRMEN'.
Can you help me to learn more?
(Other definitions for airmen that I've seen before include "serving in HM forces?" , "Red Arrows" , "they take off from the ground" , "Marine (anag)" , "Flyers" .)