It's about 7000 km, so the flight time will be about 10 hours. However, there is no direct flight from Cincinnati to Milan so you would have to add the time spent at the connecting airport(s).
A random search for departure 29May,Fri shows:
OPTION 1: 15hr 38min ($ 675 + taxes&fees)
Cincinnati (CVG) - Charlotte (CLT) US Airways Flt 2272 Dep 12:10pm
Charlotte (CLT) - Rome Fiumicino (FCO) US Airways Flt 718 Dep 02:35pm
Flight Duration: 14hr 35min; Layover Time: 1hr 3min; Total Trip Time: 15hr 38min
OPTION 2: 17hr 45min ($ 675 + taxes&fees)
Cincinnati (CVG) - Philadelphia (PHL) US Airways Flt 3764 Dep 12:48pm
Philadelphia (PHL) - Rome Fiumicino (FCO) US Airways Flt 718 Dep 06:10pm
Flight Duration: 13hr 57min; Layover Time: 3hr 48min; Total Trip Time: 17hr 45min
Flights with 2 stops take about 17hr to 21hrs, but fare is $ 345 + taxes&fees.
The flight times varies according to the speed of the flight. If the flight is flying at a faster speed then the times may change. We are providing you with standard flight timings. The flight time for the above mentioned trip is.10 hours
About eight hours and five minutes, depending on jet stream, of course.
10 hours
A typical flight between LGW and Cincinnati, OH would have a flying time of about 7 hours, 56 minutes.
A typical flight between Cincinnati, OH and Greenville, SC would have a flying time of about 38 minutes.
Cincinnati, OH (CVG) to Detroit, MI (DTT) Shortest Flight Duration 1 hour 7 mins
A typical flight between Dallas, TX and Cincinnati, OH would have a flying time of about 1 hours, 38 minutes.
One hour and thirty minuts
The flight distance from Cincinnati, OH to Maui is about 4,380 miles.
New York, NY (NYC) to Cincinnati, OH (CVG) Shortest Flight Duration 2 hours 11 mins
How long is the flight from cincinnati OH. to San Juan Puerto Rico
10 hours
Cincinnati OH is already in Ohio.
lots
2 hrs