What time to arrive at airport

Since it is a domestic flight and early you could cut it as close as 5, but 4.30 would provide a little cushion. There will not be long lines at security. Don't make the mistake of going to Terminal 5 thinking it is an international flight home. Use the regular terminal 3.

Having taken crack-of-dawn flights in the past, I wouldn't assume lack of crowds just because of the early hour. Better to arrive by 4:30 AM than be shocked at finding long lines when you walk into the terminal.

At least one hour prior to departure.

But for Fiumicino airport I like to get there about 75 to 90 min prior even for a EU/Schengen flight.

Thanks... I'll be there early. Any recommendations on a hotel close to fco??

If you are in Rome the days prior to your flight it is not worth it to change hotels just for the last night. A taxi can take you to the airport in 30-35 min at the time in the morning from virtually anywhere in the city center. Frankly I'd rather stay in the city center on my last night in Rome.
if you insist on staying at the airport, Hilton inside the airport is the closest and most convenient option (although not the cheapest), any other option would require still at least 10-15 minutes. So to me the choices are two: either stay downtown on your last night or splurge on the Hilton at the airport.

Thanks for all the information!

We flew from FCO to CDG (Paris) & then on to the U.S. and our flight departed Rome at around 6 30 am. I really grappled with what time to get to the airport but ultimately decided to be at the airport an hour and 45 min before departure. I was shocked to see a lot of people there. We flew Air France and the check-in process was handled by a different airline on behalf of AF and other airlines so there was a very long line just to check in luggage at the desk. I already had our boarding passes as I had checked in on line but still needed to check-in our bags. By the looks of the line, hubby and I were concerned we might not make our flight but luckily we were flying business class (with miles) & I spotted a separate line for Sky Priority and thereby circumvented the long line. We got to the gate with plenty of time to spare but both thought it would have been a very close call had we flown coach. I don't know if what we experienced is a regular occurrence or unusual but I would definitely get there at least 2 hours ahead as we needed to be on that next flight out of Paris! Just my two cents.

Oops...just realized your flight already took place. Let us know how it went at the airport!