GameMastery Guide, page 191 or so?
Astral Plane wrote:
Subjective Directional Gravity
Timeless: Age, hunger, thirst, afflictions (such as diseases, curses, and poisons), and natural healing don't function in the Astral Plane, though they resume functioning when the traveler leaves the Astral Plane.
Mildly Neutral-Aligned
Enhanced Magic: All spells and spell-like abilities used within the Astral Plane may be employed as if they were improved by the Quicken Spell or Quicken Spell-Like Ability feats. Already quickened spells and spell-like abilities are unaffected, as are spells from magic items. Spells so quickened are still prepared and cast at their unmodified level. As with the Quicken Spell feat, only one quickened spell or spell-like ability can be cast per round.
So not so much flying as falling with style.
Subjective Directional Gravity wrote:
The strength of gravity on a plane with this trait is the same as on the Material Plane, but each individual chooses the direction of gravity's pull. Such a plane has no gravity for unattended objects and nonsentient creatures. This sort of environment can be very disorienting to the newcomer, but it is common on “weightless” planes.
Characters on a plane with subjective directional gravity can move normally along a solid surface by imagining “down” near their feet. If suspended in midair, a character “flies” by merely choosing a “down” direction and “falling” that way. Under such a procedure, an individual “falls” 150 feet in the first round and 300 feet in each succeeding round. Movement is straight-line only. In order to stop, one has to slow one's movement by changing the designated “down” direction (again, moving 150 feet in the new direction in the first round and 300 feet per round thereafter).
It takes a DC 16 Wisdom check to set a new direction of gravity as a free action; this check can be made once per round. Any character who fails this Wisdom check in successive rounds receives a +6 bonus on subsequent checks until he or she succeeds.
While 3.0 did have movement based on intelligence the Pathfinder version is identical to the 3.5 version.
