I use ProjectAI as mentioned above and I think they're pretty good, but some of the flightplans are outdated (using aircraft that arn't being used anymore) and
some of the aircraft have what are called "mipmaps", basically they make your textures blurry when looking at the plane from an angle. So in order to get rid of them you can download a program from the internet called DXTbmp, open the texture in there, make sure "include when saving" under the "mipmaps" section on the right is unchecked and then you can just resave the texture.
So actually, if you look at the overall picture, there are probably better places out there than ProjectAI, but I don't know where.