One of the new features in Plane Maker 10.40 is a variety of classification information available for aircraft files, found in the Standard > Author window.
These fields are not currently in use in the X-Plane user interface, but we do plan to use them in the future---we want to do away with clunky folder-based browsing of aircraft. Instead, we want to allow users to browse & search through their aircraft in a much more flexible way: by aircraft name, manufacturer, category (general aviation, airliner, glider, etc.), and design studio.
So, for instance, you might want to see just the planes that were developed by Carenado, so you would select Carenado from the aircraft studio dropdown. Or, you might want to see just the general aviation planes built by Cessna, so you'd select General Aviation from the category dropdown and Cessna from the manufacturer dropdown. Or, you might want to search for all the aircraft with "747" in their name, and see your 747-100, 747-400, etc.
We think this will be a serious improvement over folders, which allow you to organize your aircraft in only a single, fixed way.
But, before that happens, we'd like to get as many aircraft authors on board as possible---we can't know, for instance, which design studio created an aircraft unless you add this info to your ACF files.
So, grab 10.40, open Plane Maker, and add this classification information to the aircraft you develop!
(As an aside, you might be wondering... what's the difference between the aircraft's "author" and "studio"? The idea here is that the "studio" is the group producing the aircraft---you want your "studio" to stay consistent for all the aircraft your group produces, while the "author" field credits the actual people involved in the plane. Your studio might be "Amazing Sim Planes," while your "author" field might be something like "Jane Doe, flight model; John Doe, 3-D modeling; Jack Jones, texturing.")