If you had a choice of flying into Paris or Madrid,

I flew into Paris last week and it was pretty quick getting through passport control even though they had a system problem and the automatic gates weren’t working properly. We went through an agent and he didn’t even scan my passport. Or look up or say a word. 😄

Unfortunately we had rented a car and we were stuck in the circle of hell around Paris for two hours before we finally popped out toward Bordeaux, our destination. Several days and bottles of wine later, all is forgiven. 😄

I haven’t ever flown into Madrid. 

We flew through Paris last month and it was easy! Our flight to Paris was even late and we were a bit scrunched for time, but we sped right through everything and made it no problem. And everyone was SO nice which wasn't what I had heard.

Our other flight was through Amsterdam and we found it harder to navigate and the people not at all friendly.

Madrid airport is not as large as Paris, so that is a factor in how much time you need. I've never had to go through customs at either or transit, as I've only flown in and out on a within EU flight.
All signage in the airports - and this is true pretty much across Europe - will be in the local language and English. In all my years of traveling, I have found airports seem to err on the side of MORE when it comes to signs.
As to not speaking the local language - be polite and not loud and shouty. In tourist places, there will be people who speak English, if you need to ask for help. As someone else said, saying Hello in the local language, then asking if they speak English will get you a better response than just barging up to someone and speaking in English. One 'advantage' of speaking English is that it tends to be most European's second language, so many speak it and it is also used as a 'bridge' language - I have heard many conversations where, for example, a German and Spaniard speak to each other in English as that is the only language they have in common. It's not just the Americans (and Brits, and Aussies) speaking English!

I had a bad experience with one very unfriendly staff member in a train station in Paris, but all other contact was perfectly fine. My husband travels a lot for business and has a lot of experience with airports. He hates flying out of Paris. A couple of times it took him hours to clear security. I can't remember if it was a strike or what happened. Whatever you decide, use Google translator to help you communicate. Almost everyone will be kind if you at least make an attempt. Well except for the extremely mean lady who worked in the ticket booth at the Paris train station.

As a citizen from the EU, I can't really help you with the customs question although travelling in October means you won't deal with the extremely busy peak tourism season in either airport.

For purely travel/sightseeing reasons, I'd go with Madrid. I absolutely love Spain in October for the climate, the colours of nature, the sunshine, etc. If you know or learn some basic Spanish by then and use a translator app on your phone, it shouldn't be a problem whatsoever making your way to your destination between Biarritz and Pamplona.

Both routes will be scenic and nice so pick as you please. Are you renting a car to go to your destination or taking the train? The train situation should be your deciding factor if you aren't driving.

I was wondering whether it was the Camino de Santiago... I think for the experience of the trip as a  whole, it would indeed be nicer to fly into Paris in that case. You'll get to do both airports and prolong your from-France-to-Spain route that way. 

From Paris to Saint-Jean-Pied-de-Port appears to be a little over 6h by train. Super easy and a great way to enjoy the changing landscape while you rest. Absolutely my favourite way to travel over here!

The Conqueror has the Camino challenge with a beautiful medal. I think it'd be super fun to do a virtual challenge IRL. Maybe something to look into before you leave so you can start the challenge as you begin your walk? 

This sounds like a great plan and a beautiful way to earn this pretty medal. I love that they focused on the scallop shell for the back. Very striking. 

I hope you'll keep us in the loop re: final decision for the arrival airport and trip in general. It's a beautiful time of the year to be doing this walk. I live on the French Mediterranean shore and that late-late summer is usually lovely. I'd love to hear more about your Camino experience.

I don’t think it makes any difference.

They are in their mid 60s, but have been active all their lives. Her videos are calm and full of nature, animals, and reviews of the accommodations where they stayed. And food!