Risky adventure involving a day in flight (8)
I believe the answer is:
escapade
'risky adventure' is the definition.
(I've seen this before)
'a day in flight' is the wordplay.
'day' becomes 'd'.
'in' is an insertion indicator.
'flight' becomes 'escape' ('escape' can be a synonym of 'flight'**).
'a'+'d'='ad'
'ad' going into 'escape' is 'ESCAPADE'.
'involving' acts as a link.
(Other definitions for escapade that I've seen before include "Adventurous incident" , "Wild adventure" , "A reckless or mischievous adventure" , "A piece of reckless or mischievous conduct" , "Madcap adventure" .)