I've seen airports with their name as 'S18' or 'O69' or something like that and I am wondering what that letter before the number means, and well, what the number also means. How is it generated and upon what rules is it called that?
Also, I know that for things such as aircraft registrations and probably airports as well they have a letter at the start to sort of designate the country. I believe 'G' is for England, but what is the proper name for all this and where can I find a full list of what all the letters mean?
Cheers