The only time I have ever seen this "Aviation Meta" SE is when a question in "Aviation" has been migrated. What if I want to ask something in meta? I don't see it in the list of all SE sites, or a link from Aviation. Is there a secret moderator trick to get here?
Another option is to just bookmark it, or do it the way I do and type the URL. The main site is the site starting with "a" that I use most, so I just type "a" and Firefox autofills it. To get here, I type "aviation.m", then it autofills.
Every SE site has one of these "meta" sites; just put ".meta" before "stackexchange.com"; e.g. Law SE's meta site is https://law.meta.stackexchange.com. There's a network-wide Meta too; it's at https://meta.stackexchange.com. For sites like Stack Overflow and Ask Ubuntu that don't have SE domains, just put "meta." before the domain, e.g. https://meta.askubuntu.com.