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.