I wonder if the Flying Blue Air France/KLM credit card would prevent miles from expiring? I don't know, but perhaps an option worth looking into:

https://www.flyingblue.us/en/financi...ank-of-america

This one above for Americans I think (or at least drawn on American bank).

The card is reasonable cost and I've been considering it, but haven't looked into whether or not it prevents miles form expiring if you "earn" miles by using the card. For American Airlines, having a card and thereby generating miles from purchases creates "activity" on the AAdvantage account. And that activity prevents all miles accrued (by whatever means) from expiring. I've found it to be useful, since I use AA less these days.

Don't know if same logic applies in this instance with Flying Blue Miles