Air support on course to cover Matthew and son (8)
I believe the answer is:
televise
'air' is the definition.
(I know that televise is a type of air)
'support on course to cover matthew and son' is the wordplay.
'support on course' becomes 'tee' (golf tee on a golf course).
'to cover' is an insertion indicator.
'matthew' becomes 'Levi' (synonyms).
'and' is a charade indicator (letters next to each other).
'son' becomes 's' (genealogical abbreviation for son).
'levi'+'s'='levis'
'tee' going around 'levis' is 'TELEVISE'.
(Other definitions for televise that I've seen before include "Show" , "Put on TV (S, not Z)" , "Screen" , "Put on the box" , "Air, broadcast" .)