Flyer heralding a lovely short film (7)
I believe the answer is:
titanic
'film' is the definition.
(I know that Titanic is a film)
'flyer heralding a lovely' is the wordplay.
'flyer' becomes 'tit' (type of bird).
'heralding' is a charade indicator (letters next to each other) (some letters come before others).
'lovely' becomes 'nic' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'tit'+'a'+'nic'='TITANIC'
'short' acts as a link.
(Other definitions for titanic that I've seen before include "Huge, epic" , "In attic (anag.)" , "Giant" , "Twenty one [SHIP]" , "Huge, like doomed liner that struck iceberg" .)