In the above example I would be tempted to put it in the aircraft section. I visit different forums like most of you do I'm sure. It's really crappy when a site has tons of headings. The cleaner it is the better. If it is too cumbersome to navigate then less people will stick around. It's nice to be able to just pop in when you are busy and not have to go through a big list of headings just to see whats new. Headings within headings get complicated and time consuming...less time for building.  That's my 2% of a loonie.