Hi flitezimz. I believe that AF99 is simply an updated version of the original Aircraft Factory (FSFS). You might find a copy on Ebay.
I note from your other posts that you create aircraft for CFS2. Not many people use AF99 these days as things have moved on & it's limited compared with later 3D modelling applications. You might like to take Stratobat's suggestion & try Gmax which is a free download.
http://www4.discreet.com/gmax/Alternatively, create a few aircraft for CFS1. I've seen requests on this forum for FS98/CFS1 aircraft that seem to have been overlooked.