This is really good thank you. Worthy of a follow-up submission on HN of its own since we're pretty deep into comments here.

Note that this study is specifically focused on North Carolina. I'm curious if similar research has been done in the Western US. California in particular is very popular for GA. Here's the top 10: https://generalaviationnews.com/2020/02/03/top-10-busiest-ge...

edit: Another link: Santa Clara, CA recently banned sale of leaded fuel https://grist.org/transportation/california-county-bans-toxi...