Flight O'Hare International Airport departs from Chicago O'Hare International Airport at 15:15 and arrives at Montreal Pierre Elliott Trudeau International Airport at 18:23.
The flighttime is about 2h 08m. The distance travelled ("as the bird flies"): 1575 Km. So the average speed is roughly 738 Km.
There is an 1 hour time difference between Chicago and Montreal