Jaggedy textures is commonly from not having antialiasing turned on and possibly not having global texture size to maximum in the display settings of FS9.

What I use, as well as many other simmers, is a program called Nhancer. Google search it, download and install it. Very simple to use and will remove the jaggies for sure. Once you install Nhancer, TURN OFF antialiasing within FS9, as it will conflict with Nhancer and you will still see jaggies if you don't turn it off. Also, you can set AF within Nhancer or within your graphics card control panel.

Good luck....