Flight O'Hare International Airport departs from Chicago O'Hare International Airport at 05:01 and arrives at Atlanta Hartsfield Jackson International Airport at 08:12.
The flighttime is about 2h 11m. The distance travelled ("as the bird flies"): 390 Km. So the average speed is roughly 179 Km.
There is an 1 hour time difference between Chicago and Atlanta
