Flight Leonardo da Vinci–Fiumicino Airport departs from Rome Leonardo da Vinci–Fiumicino Airport at 09:05 and arrives at Los Angeles International Airport at 13:20.
The flighttime is about 13h 15m. The distance travelled ("as the bird flies"): 14491 Km. So the average speed is roughly 1094 Km.
There is an 9 hour time difference between Rome and Los Angeles