I recently installed FS98 on an XP machine and some of the aircraft models don't show up.
Most aircraft work 100% fine but some models don't work.
For example the 4th plane on this page - "Lufthansa Cargo DC-8-71F for FS98/2000".
http://www.simviation.com/fs98jets96.htm
My FS98 can't load the model for some reason.
I have converter and patch installed and I tried running in Windows 98 compatability mode - nothing. The plane should work in FS98, the screenshot is in FS98.