Connecting Flights to Rome

Given what you've noted I'd pick the 6 hour layover in Frankfurt and see if you can buy iinto a lounge

Personally I would do a shorter leg in the US with a direct flight from a major US city -- Chicago, Atlanta, New York???

Personally I would do a shorter leg in the US with a direct flight from a major US city

We have the opposite philosophy -- ours is never connect in the US. If worst comes to worst and you miss your connecting flight there are far fewer subsequent flights across the Atlantic than there are flights within Europe. And you can take a train in Europe as a fallback plan; no trains across the Atlantic.

Zurich is the smallest airport of the three. If the flight goes directly from SFO to Zurich, I would choose Zurich. It has the least layover time and has not had the issues FRA has had with airport mayhem and Lufthansa strikes. Both MUC and FRA have had issues the last few years. In Zurich those issues have not occurred and Swiss Airlines seems to be the most reliable. “To be on time, go with the Swiss every time.”

Check Delta

Next June is 9 months away! I would never book that far in advance as too many things can change. Including the prices.

I guess it comes down to opportunity cost. If a 6-hour layover would make you feel the safest & ensure you get to Rome that day, maybe saving you from paying lost night’s lodging in Rome? (I would hate it, & risk the Zurich connection.) But I don’t mind calling UA in the US to rebook, which you’d have to do as paid & ticketed by UA. I’ve done this a few times due to missed connections & it’s always worked out. Could you call UA first and ask what flight they’d book you on if you miss your Zurich connection? We NEVER transit in the US, same reasons as mentioned by John above. And I would probably wait, track prices & wait to purchase. I seem to recall UA changes it's schedule every 3 months, so things might open up.

Have you checked British Airways? We've had good luck with them. Our philosophy is to try to get out of the USA on the first flight. Wherever you're connecting to in the USA might only have one flight at day to Rome. If you can get to a hub like Heathrow, there are probably more flights. If you are leaving from San Francisco, have you thought about going the other direction? At that point, it's about equidistance. Maybe UAE to Dubai. I'm not sure if it will work for you but it's a possibility you can think about...

Maybe this is obvious, but the other reason we try to have our layover be in europe is that at least the airport in Amsterdam or Zurich or wherever is going to be INTERESTING but a US airport is probably not.

A 4- hour layover is what we aim for, but we do put up with the 6-hour ones if we have to. Less than 3 would make us real nervous.

I have several times connected in Zurich on tighter connections than that. It has not been an issue. In fact, the routing I am favoring for next May trip has me going through Zurich with a tighter connection than that.

The fact that there is another trip to Rome that day would comfort me, although it could, of course, be full.

I think it depends on your risk tolerance. Most of the time overseas flights make up any time they lose. I have connected twice in USA and one of those times the flight was so delayed from Florida to JFK that we missed our flight to Milan. And we had a four hour layover! We made it there via Paris but shows no guarantees no matter how conservative you try to be.

First thing I would do is take a good, hard look at the details of the seat I would be sitting in on that first, long flight from SFO to Europe. United has many different aircraft, they are not all the same and neither are the seats. My seat comfort (or lack thereof) for the long flight would be one factor, among the others already mentioned.

(Yes, it's very possible flights and aircraft and layovers may change between now and next June, possibly more than once; that's beyond your control, if you want to book now, that's part of the equation, too.)

We too are flying to Rome next June. We change planes in Montreal. We have a 4 hour connection time. Our other option was 1 hour. It’s an Air Canada flight. Flying back from Milan is better timing.

Yeah, I saw that Air Canada flight. It's definitely the cheapest option, but TBH I'd rather pay an extra $100 so I don't need to arrive at SFO at ~4:00 a.m.

It’s definitely gonna make for a long day but I’m up for it. We haven’t traveled internationally now for 3 years. The good old Covid years.

My choice is Option 2: 6 hour connection in Frankfurt

Allows for arriving late in Frankfurt, allows plenty of time to disembark plane, use a bathroom, go through customs and best of all grab a Dunkel or two, a meal and apple strudel for dessert.

I'm so glad @nancys8 said it, wherever you transit in Europe is going to be more interesting than being stuck in a US airport. BTW you can pay for Frankfurt lounge access, though it's not cheap, about $65. And most Lufthansa lounges have showers, check if they are open, but that could make it worthwhile. https://www.loungebuddy.com/FRA.