Nice or Marseille airport for return to USA from Avignon

I'd base your choice largely on the kind of flight you can get home from France. My guess would be your cheapest flight and most direct flight would be from Paris, but I don't know where you are flying home to or when, so I couldn't say. Obviously if you take the train anywhere you need to factor in the cost and time of getting from Avignon to the departure city and airport.

Since it's only a 1 hour drive from Avignon to the airport outside of Marseille, I'd drive and drop the car at the airport unless there was a major cost/time savings to fly back from Paris. You would have to compare flight departures from each as well as schedules traveling from Avignon to Paris by train. If the stars align perfectly, there's a chance you could drive to MRS the morning of your flight. If not, in either case, you might have to travel to the departure airport the night before. Nice is over three hours from Avignon so I wouldn't consider that.

I agree with the points made above. If you get a "cheaper" flight from Paris, how much will it cost you, in time, money, and hassle, to get there from Avignon, compared with Marseille? With the departure times, will you need an airport hotel the night before? Figure all of this out before making a final decision.

Sometimes flying home from Marseille costs about the same as flying home from Paris, and sometimes it's much more. You just have to look for your travel dates and home airport.

I agree that Nice isn't a convenient airport for your needs. It's about a 3 hour drive or train ride from Avignon, and probably not cheaper than Marseille, and (unless you're going to JFK) has no nonstops back to the US. If you're going to change planes and/or pay extra anyway, you might as well leave from Marseille, which is much more convenient. Because the Avignon to Paris train line is high speed but the Avignon to Nice train line is not, each takes about the same amount of time - even though Paris is MUCH further from Avignon than Nice is!

Do be sure you are looking at "multi city" flights rather than two one ways. And note that while Marseille airport doesn't have nonstops to the US, it has connections through lots of hubs besides Paris - Madrid, Frankfurt, Amsterdam, London, etc.

You might look at the two direct flights from Marseille to Montreal which is a short hop to Boston.
I did something similar flying from Nice to Montreal and than to Chicago on Air Canada

Marseilles is logistically sweetest. Note that Nice and deGaulle are both about 3 hours from Avignon by rail, if MRS does not work out.

There are convenient high-speed TGV trains that go from the Avignon TGV station directly to CDG in about 3 hours (there is a very quick 10 minute shuttle train from Avignon Central station to the Avignon TGV station), and several hotels literally within walking distance of the CDG TGV station. My wife and I did exactly that back in October and it was really convenient. It was really nice to get to the airport area the night before our return flight and get an OK hotel meal and a very good night sleep. This is probably much more convenient than having to change planes somewhere since there are very few direct flights to the US from either Nice or Marseille to the US

Kathy, I am flying from MRS (Marseille) to Boston on Tap Airlines with a stopover in Lisbon.
Returning the car at MRS.

Why not change your rental car drop off to MRS? most rental car contracts can be modified so it may not cost anything.

Was the cheapest flight I found but also they offer the nice option of a multi-day stopover in Lisbon so 2 trips in one both with direct flights! Cost was the same for Marseille or Nice in this example.

You may be able to get a better rate flying direct from Paris to Boston on Primeria or Norwegian from Paris ; I am not sure.
The other low cost options are WOW and Iceland Air. Both have a stop in Iceland so not sure their cost will change much Marseille or Paris.
If you only need a one way fight ; many of the airlines will not give a competitive rate so your list is likely no more than the above unless also looking at R/T or reward point flights.
Nice for you makes zero sense.

I saw someone above mentioned the MRS to Montreal option but in my experience while close Montreal to Boston; it is an insanely over priced flight.