Flight Leonardo da Vinci–Fiumicino Airport departs from Rome Leonardo da Vinci–Fiumicino Airport at 09:20 and arrives at Chicago O'Hare International Airport at 13:10.
The flighttime is about 10h 50m. The distance travelled ("as the bird flies"): 11136 Km. So the average speed is roughly 1028 Km.
There is an 7 hour time difference between Rome and Chicago