A couple of times a year I get emails from people asking about where I founf whatever airplane I was flying and how much did it cost. The answer is that every single plane in my archive (over a hundred) are freeware from xplane.org.
See, when people go looking for aircraft they are only looking within their version, and most of the really great planes are all payware nowadays. But the org has stuff going back to version 8, and a lot of that stuff was really well done. So if you are not afraid of using planemaker, you can use those old aircraft, and use planemaker to convert them to the current version. After that you usually have to rebuild the instrument panel (for the older planes) but it's easy to simply import panels from existing aircraft.
So you can have hundreds of aircraft if you are willing to bring them up to date. There really are some crazy craft out there for free. One guy built a carrier--the Nimitz-driveable. I have an Xwing someone built back on ver 7 (doesn;t fly very well.) Or the GDI Orca, that thing is way cool (if only it didn;t crash all the time!)
What I have a hankering for is to locate the original X1 from version 6, update that, and fly it again. There were a few planes in the older versions that Austin deleted for some reason. Anyone remember the Douglas X3 Stiletto?