Combat Flight Simulator...new ad ons

Here are some nice sites, there are more but for now I'm sure you will find what you like.
Just use CFS2 for your sim.

http://www.simviation.com/fsdcfs%5B1%5D.htm

Heres one at avhistory.org they use 1% planes. Be careful though, alot of peeps are getting mis matches but they are being fixed. There is a site called mudpond,

Thats all i can think of, use the search bar and you may find more.