Hello! I have been persuaded that instead of trying to fly from a Greek island (e.g., Naxos or Santorini) to Athens and then connect immediately to an international flight back to the U.S., it's much safer, in case of delays, to spend one night in Athens before trying to fly home. Assuming that's true (but correct me if I'm wrong!), is there a hotel you recommend for spending a single night before flying back? We will have already had a few days in Athens. Thanks!

All depends on the time at which you must be at the airport for your flight home.
A late arrival at Athens if your outbound flight is in the morning wouldn't solve any problem.
For a one day stay on the mainland, you can just chose the place that suits best your interests.
If it's Athens, I would chose a hotel close to the metro line to the airport (Syntagma, Monastirion.....)

If you’re flying out of Athens soon, I suggest these two areas for your last night in Greece:
- Syntagma
Stay right in the heart of Athens, close to everything. From Syntagma, you can take the Metro Line 3 (Blue Line) straight to Athens International Airport in about 40 minutes. For a comfortable option, check out the Emerald Hotel, just steps from Syntagma Square.
- Artemi
If you prefer a quiet evening close to the airport, head to Artemi. It’s a calm area, about 10–15 minutes from the airport. A convenient place to stay here is the Airscape Hotel.

If you don’t mind the high room rates there is the airport Sofitel. I’ve stayed there a couple of times before an early morning flight, and like the sheer convenience of walking across the street after checking out in the morning, and taking only about five minutes to reach the airline check in counters. There is not much to do at the airport, but you can walk to the terminal to use the free wifi (they charge for wifi in the hotel).

Another hotel near the airport is Hotel Avra in Rafina. It’s about 20 minutes by taxi to the airport. There are also frequent buses back and forth, and the buses from the airport stop across the street from the buses to central Athen and Piraeus. I’ve also stayed there a couple of times, and highly recommend it. Rafina is a smaller ferry port than Piraeus, and has some good fish tavernas.

I really liked Air-In in Spata Artemida. It's about 12-15 minutes from the airport and cost about $160 for a night (Friday-Saturday).

If I had no time, I'd stay very close at a hotel with an airport shuttle.

If I had the time and inclination to squeeze one last bit of vacation out of the experience.... I'd go to a nearby town like Peanaia, eat at the atmospheric Taverna Chouneri, visit the Holy Church of Christ's Birth (!) and the Vorres Museum. You are a 15 minute taxi ride from the airport. This is something I would really look forward to.

And I am sure I would not fly on a separate ticket the day of my transatlantic flight. Unless I didn't really have to go back.

HOTEL AVRA has a FREE shuttle from/to airport 24 hr/7 days... Only requirement is that you book the shuttle at same time you book the room. Rooms on one side overlook the beach ... tree-shaded tiown square is a few hundred yards away. You coul spend your last evening feeling you are still iln an island village, not that you've returned to Big City.

If the timing of the flights work and if they are on the same ticket (not necessarily the same airline), you should be OK to fly from an island to the US and if there is a delay, it would be up to the ticketing airline to get you onward. I think it depends on the timing. I wouldn't want to do that if my flight from Athens to the US was the last one for the day. YMMV.

Thank you for these amazing recommendations! I will explore them all!