Which airport to fly into to begin the Camino Frances?

The closest airport to SJPdP is Biarritz airport (BIQ). Take the urban bus to Gare Bayonne and take the SNCF TER train/bus to SJPdP.

One thing to consider is how you will get home from Santiago (SCQ).

Neither of these airports has oversea connections so you will need to reach a major airport first.

There are several discount airlines in Europe. Ryan Air and Easy Jet are just two of them.

I went YVR to London Heathrow. I took a bus from Heathrow to Stansted. I flew from Stansted to Biarritz with Ryan Air.

On return I went from Madrid to London Gatwick with Easy Jet then home from Heathrow. I could have got to London from Santiago.

Paris has good connections with Biarritz and Bayonne using plane or train.

Madrid has good connections with SJPdP ... bus via Pamplona or train via Irun and Bayonne.

There is an airport San Sebastian (EAS) almost co-located with Irun train station with flights from Madrid or Barcelona. This is the closest airport to SJPdP on the Spanish side of the border.

Bilbao has good connections requiring travel via San Sebastian and Bayonne.

Many people have connected via Barcelona, Dublin, Lisbon etc. Once in Europe its relatively easy and cheap to get around.

I've posted lots of transportation details on any option you might choose ... see the travel section.

I walked the Camino last year and am also from the USA. I flew into Paris--Charles de Gaul airport via JFK. I then too the train from Paris to St Jean--it only takes a day--train tickets are quite reasonable and the train station is located in the airport and the trains run on time (not like in the USA) and are quite comfortable. If you wanted to be a bit more adventurous and have the time, you could go into Paris from the airport and catch the train at another train station. As for the return home. I took at flight from Santiago to Madrid to Chicago and then to Ohio. I bought my tickets for my flight in June and flew the first part of October--I watched ticket prices over about 8 months and it wasn't until about four months before my departure date that they were at their lowest. If you can be somewhat flexible on your time that helps too with the prices though it can be a bit of a challenge to get your train departure time coordinated with your arrival. Though I was able to do this and arrived n Paris in the early morning, took the train and arrived in St. Jean the same day in the late afternoon to begin walking the Camino the next day. Since you are in NC you would probably need to look into international flights leaving from NY or Atlanta I would think, but am not certain about that--you can get there using a regional international airport connection. I chose this because of having just six weeks to get there walk 500 miles and get back home--it actually took me 34 days to walk from St. Jean to Santiago--not bad for being 62 yo.

I have noticed in the past there have been suggestions that travellers from the USA (and for that matter I assume elsewhere) explore open Jaw tickets. I recall something about any internal flights being linked to the return ticket so that you are covered if the connecting flight is delayed?

If you fly to say Paris or Dublin, you either have to fly or take a train from either of those places down to Bayonne/Biarritz then to SJPDP. Added expense to the round-trip from the US. My first Camino I flew to Paris and took the train all the way to SJPDP. My second Camino I flew to Madrid and took the bus to Pamplona. That bus ride was very cheap. The station is at the airport. From Pamplona you can then take a bus to SJPDP. Also cheap.
Of the two, I spent less flying to Madrid and busing to Pamplona.