Tivoli to FCO by car

Are you refueling before returning the car? I would give myself 2 hours from departure to time at check in desk, to allow for driving the distance, refueling, possible traffic snarls, getting lost, getting into the correct parking structure to return the car (A,B,C depending on car rental company), car rental return, and walk to the terminal.

I usually stop at the rest stop linked below to refuel when I drive to FCO, coming from Tuscany, however since you come from Tivoli it is likely that you will take the Circonvallazione Meridionale (Southern Beltway) rather than the C. Settentrionale (Southern). In other words you will take the GRA (Grande Raccordo Anulare, or Grand Circular Beltway) clockwise on the south of the city rather than counterclockwise through the north. I’ve never had to take the southern GRA (clockwise to the south) so I don’t know where the “area di servizio” (service area) are but you can also take the GRA clockwise, to the north, and stop at my service area below. It might be a few miles longer that way, but I don’t think significantly more in time, since the southern side of the beltway is usually more congested, at least on weekdays (but probably not at 6.00 on a Saturday). If you take the southern clockwise route find a refueling station on Google Maps, preferably one at a rest stop like the one I linked, so that you don’t have to exit the beltway and re-enter.

https://maps.app.goo.gl/vnzeGEUXtS5PEe7A7?g_st=com.google.maps.preview.copy

I've done the drive from Tivoli maybe 8-10 times over the last five years (well usually from farther east in Abruzzo, but passing Tivoli.) Roberto's advice is detailed and spot on as always. I'll add one thing (from experience). The GRA is indeed a circle and thus you can get to the airport on it from either direction. I have messed up the exit twice due to confusing signage and chosen the "wrong" way on purpose once due to an accident backing up the way I wanted to go. Don't panic, it's a similar drive time whichever direction you go on the loop. I would not bother exiting and backtracking if that happens to you. Getting off and back on the other way is likely to be far more confusing than just carrying on and looking for the airport signage.

Still, allowing lots of time is always a good idea, so I second Roberto's suggestion of two hours even on a Saturday morning. Again, if something happens, don't panic because FCO is very efficient to get through even when busy. But 6 am or a little earlier will be comfortable.

Note that Google Maps gives the drive times for the best routes at the time you checking, so check right before leaving your hotel in case traffic conditions have gone screwy.

Thanks everyone for your great tips and suggestions!

Jim