The spell Wind Walk makes you "insubstantial" as per the spell Gaseous Form, which gives you DR 10/Magic, some immunities, and your armor doesn't contribute to AC. During this time you can fly at 10ft per round, and I understand that combat happens normally (you can get hit at your new AC, you apply DR etc.).
My question is what happens when you use the magical wind aspect of the spell.
If desired by the subject, a magical wind wafts a wind walker along at up to 600 feet per round (60 mph) with poor maneuverability.
How does combat affect someone in this state? Do they have normal AC and moving through threatened squares provokes AoO? Do they get some AC bonus or avoidance for moving at 600 feet per round?
I feel like this is mostly a travel spell, but could have interesting applications in combat scenarios.
Best Answer
The rules don't specify any bonuses for moving at those speeds in combat, or using Wind Walk at all in combat. It wouldn't be unreasonable for a GM to give you an AC bonus for being so hard to hit, however.
The real problem with using Wind Walk in combat is this section from Gaseous Form:
and this from Wind Walk:
Wind Walk prevents you from performing most offensive actions, and it takes five entire rounds to leave vaporous form. Many combats last less than five rounds to start with. Wind Walk is designed to exclude combat and really only be useful for travel.