We will be flying out of Rome (FCO) on Saturday on an 11:05 flight on USAir. How much time should we allow to get from the Trestevere area to the airport via a private transport, check in and get to our gate in time to board?
If it is a direct flight back to the US, in theory you need to be there three hours in advance and you might cut it to 2.5. But it is mid day and it can get zooish at that time of day in FCO. Since you should be there around 8 you will be going in a heavy traffic period. Thirty, 45 minutes should get you to the airport and another 15 to the check in point, after that it is anyone's guess. Probably an hour to check in and clear security.
Pat I took a taxi from the termini area on Saturday July 2nd of this year. I think because it was Saturday the traffic was much much lighter than when I have taken this trip on a weekday. Other than stopping for traffic lights the driver was going the speed limit (or more) and we made it quite quickly. The dedicated Terminal 5 for US direct flights is a vast improvement over Terminal 3. I arrived at FCO around 8 am and checked in (On United) and they had no waiting line. Security was a snap. I did my waiting (at least 2 1/2 hours) seated in the gate area. Doing your waiting seated at the gate is better than standing in a check in line. Again I think the drive was so quick because it was the weekend. IMO it is a travel day and no matter what you do it will include a lot of waiting. But with an 11 AM flight you can get a good nights sleep, get up at a reasonable time (be sure to pack the night before), have your hotel breakfast, have your transportation show up around 7:15 - 7:30 and you should be at FCO around 3 hours before departure.
That was my experience in July. However be sure to ask your hotel and private transportation provider to see what they think is best. Robert