Flyer may see cause of trouble crossing one place (7)
I believe the answer is:
biplane
'flyer' is the definition.
(biplane is a kind of aircraft)
'cause of trouble crossing one place' is the wordplay.
'cause of trouble' becomes 'bane' (as in the bane of one's life).
'crossing' means one lot of letters goes inside another.
'one' becomes 'I' (Roman numeral).
'place' becomes 'pl' (abbreviation used in postal addresses).
'i'+'pl'='ipl'
'bane' enclosing 'ipl' is 'BIPLANE'.
'may see' is the link.
(Other definitions for biplane that I've seen before include "Aircraft with double wings" , "flying machine" , "Early aircraft" , "Old aircraft" , "craft" .)