From my own anecdotal experience, JFK
flights often do fly right over YUL
(especially in winter, it seems, presumably to avoid unfavorable winds), but as Timz pointed out, they would all fly over sometime in the early afternoon since they all depart by midday. Ditto for the IAD
and daytime JFK
nonstops leave at 2:45 and 3:15, respectively, which--if they were to overfly YUL
--would pass overhead about an hour later (or perhaps a bit more, if delayed for whatever reason). Is that the approximate time frame, Myk?
Common sense is not so common. -Voltaire