I already do this, so I’m in. GA flying is so underappreciated in this community, but it’s really a lot of fun!
I doubt the last unvisited airport will be in the USA, and especially not in somewhat popular places. I’ve been to 0CO2, Savannah, Portland, and of course New Orleans.
And could it be possible that the developers have the numbers of spawns and/or landings at each airport? Or that the airport editing team has a list of airports that they haven’t even looked at?