Alter Aeon Online Help

Keywords are:  'airborne biomes'

There are a few varieties of airborne terrains:

air     - empty air, nothing to stand on or hold onto. Cannot be moved through
          without some kind of magical support.
cloud   - banks of clouds, often magically stabilized. Found primarily in the
          elemental plane of air but can manifest in other planes.

Airborne terrains are difficult to traverse without magical assistance, and
often resource poor. They are fortunately quite rare.