FCO timing question - not booked through

Is the Iberia an international flight from the States? If so, be aware that it might be a VERY long walk from your arrival terminal to the Alitalia terminal. If one of you is a slow walker, and needs to take occasional breaks, then the 8:05 might be wiser. If you all can walk a mile in 15 - 20", then the 5:15 would probably be okay.

The Iberia flight is arriving via Madrid.

If arriving from Madrid, there would be no immigration since you are now in the schengen zone. Three hour should be adequate if everyone is on time. Although a lot of airports in general tend to back up later in the day. But if your flight is delay, the other flights will probably be delayed as well. But to be absolutely safe, I would book the 8.05.

If everything is on time, and you only have carry on luggage, 3 hours is plenty. The question is, what will you do if it's not enough time?

What I did (arriving from the US in Rome, and getting a flight from Rome to Palermo on a separate ticket) was buy two tickets. One was 3 hours after my scheduled arrival, and one was 10 hours after. This way, I knew I'd use one and discard one, and the combined cost of the two advance purchase tickets was still less than a last minute ticket on that route for my date (a Monday, when fares were jumping). In the end, I made the three hour "connection" with time to spare, but of course that wasn't guaranteed.

So, look now at the price for the full fare, fully refundable ticket on your route. Look at all the airlines that fly this route (I know Ryanair and Alitalia do - not sure of others). If it's affordable, buying a last minute ticket can be your back up plan. If it's already very expensive, consider doing what I did.

Note that when I flew this in 2014, (so it could have changed in the interim), the Alitalia's International website https://www.alitalia.com/en_en/ had the same prices for domestic flights as their Italian website https://www.alitalia.com/en_it/. Their US website https://www.alitalia.com/en_us/ had much higher prices for these flights. Check all three to see which one is currently offering the best deal.

Thanks for these replies. I actually thought I would book the 8:05 ticket, and then see if I could fly standby if I arrived earlier. I called the airline and they said that they don't accept standbys. I also asked what would happen if I missed my flight, and agent said that they would put me on the next one--but, something about that seemed off! (If someone could confirm that they do, indeed follow the "flat tire" rule, that would be great.)

As an update: I just talked to a different rep who told me that I would have to buy a new ticket (as seems normal) if I missed my flight.

Thanks for reminding me about the Schengen zone thing. I did do a double check on the time it would take going through immigration in Madrid....

We flew iberia from jfk this summer and were delayed four hours on the tarmac at jfk.. Hence missed our flight from from madrid to fco and lost our nonrefundable Alitalia tickets from fco to venice. Spent the night in Madrid because it was cheaper to book another flight the next day direct to venice from madrid vs. Taking Iberias last flight out to Fco, only to hang out in an fco nearby hotel. All last minute flights or train tickets from rome to venice for a family of 5 to venice would have cost us a lot more.

Mackpackof5: thanks for sharing the story and sorry this happened to you. So, so much can go wrong when traveling....