Air Walk

Transmutation [Air]
Level: Air 4, Clr 4, Drd 4
Components: V, S, DF
Casting Time: 1 standard action
Range: Touch
Target: Creature (Gargantuan or smaller) touched
Duration: 10 min./level
Saving Throw: None
Spell Resistance: Yes (harmless)
Description

Other Information
Subject can walk on air or use on a specially trained mounts so they can be ridden through the air.

Pros:

Can affect virtually any creature, regardless of size.

Can affect mounts.

Since walking on air is like walking on the ground, subjects retain their full natural mobility, similar to perfect flight.

Cons:

Half speed while ascending/descending.

Doesn't last long enough for large-scale aerial travel.

Tricks/Combos:

The best "trick" I can think of with Wind Walk is to cast it on your mount and not use the ability right away, saving it for a huge surprise. One possible scenarios would be leaping off a cliff to make opponents think you have died, and then escaping in mid-air once you're out of sight.

Overall:
Wind Walk is a useful spell for Clerics, who have no other real way of becoming airborne. Same goes for Druids, but a Druid who uses an animal as a companion/mount gets more mileage from this spell; a dire tiger with Wind Walk could be a scary sight. That being said, the half speed while ascending/descending is painful. On a related note, although Wind Walk has a longer duration than Fly, you move a lot slower with Wind Walk, so for total distance the difference isn't that great. It's still not really long enough for any extended air travel. It will last long enough to scale and infiltrate a large castle or keep, but not enough time to explore a mountain.

Recommended for Clerics?
Not on a regular basis. For the most part you won't need to get into the air. If you know you will need some aerial travel, then it is a useful spell, but in day-to-day use this will probably just end up converted into a Cure Critical Wounds spell.

Recommended for Druids?
Not on a regular basis (unless part of regular mount/companion strategy). As Cleric, but if you already have a means of becoming airborne (through other Druid spells or Wild Shape) then Wind Walk becomes a poor spell choice. Totally different if you use it frequently for an aerial mount animal companion, as obviously it will be one of your default spells.

Recommended as a scroll?
Yes. This is one of those spells that is extremely useful in very specific situations, but only okay the rest of the time. It's much better to carry a scroll on the off-chance you'll suddenly need it rather than waste a slot memorizing it. Most times you'll have time to prepare it beforehand, but not always.