I am looking for a way to be able to select my favorite aircraft out of many different textures. Does ui_typerole have any function other than in the selection menu? If not, I was thinking of changing to "Favorites" so I could more easily get to what I fly 90% of the time.

According to the SDK the ui_typerole variable "identifies the role of the aircraft." Possible values can be "Commercial Airliner", "Single Engine Prop" or "Twin Engine TurboProp" among others. I doubt that you'll do any damage experimenting with different values, so give it a go! If in doubt make copies before you hack.

It controls how the plane is classified under the filter at the top right corner of the aircraft selection window. You can put whatever you want in it. Then, for instance, you could pull down, select WWII and see only your WWII aircraft (assuming you set up all your WWII aircraft with this typerole). Unfortunately, you can only choose one role for each aircraft, so it's somewhat limited.