This month I get a flying start (9)
I believe the answer is:
instigate
'start' is the definition.
(I've seen this before)
'this month i get a flying' is the wordplay.
'this month' becomes 'inst' (letter-writing abbreviation for this month).
'flying' indicates an anagram (letters fly around into new positions).
'get'+'a'='geta'
'geta' with letters rearranged gives 'gate'.
'inst'+'i'+'gate'='INSTIGATE'
(Other definitions for instigate that I've seen before include "Start" , "I get saint to urge or incite" , "Provoke" , "Bring about by incitement - its eating (anag)" , "Set off or stir up" .)