Considering the power boost the base races got in PF, it's not hard to make Genasi balanced against them with no level adjustment or anything. Here's my attempt at such...
Air Genasi
+2 Dex, +2 Int, -2 Wis
Medium-Sized
Base Speed 30 ft
Electricity Resistance 3
Breathless
+1 racial bonus on saving throws against all air spells and effects, increasing by +1 every five levels
Darkvision 60 ft
Automatic Languages: Planar Trade, home region
Bonus Languages: Any (except secret)
Basically I just dropped the -2 Cha (dropping the -2 Wis would work equally well, but my player wants a Sorcerer, so), reduced the electricity resistance, and droppedi the Gust of Wind SLA. I debated Gust of Wind, it might be balanced even if it were included, not sure yet. Breathless is powerful, I'll admit, but I think it's situational enough that the Air Genasi isn't overpowered compared to a PF Human or Elf.
What do you think? Please critique it as harshly as needed, since I'll be using this in an actual game. I plan to write up other planar races in Pathfinder as I get around to them. Thanks.
I've never been a fan of giving darkvision to everything under the sun and see no reason for an air genasi to have it; they don't come from a dark plane, after all. If you want a sense power, how about blindsense, instead? The genasi is sensitive to vibrations in the air, though not quite as precisely as blindsight would allow (though with later racial levels perhaps it could be upgraded).
I see you've also dropped levitation, or, as 2e put it, mingling with the wind. Perhaps this could become available later? A sorcerer might enjoy the ability to pick up a new spell-like, perhaps with options for gaseous form or even fly, later. Evocative if his genasi heritage is djinn, especially.
I'm playing an air genasi now. Breathless is mostly fluff unless you travel to an underwater plane. I've only used it for swimming so far (and avoiding having to smell /stinking cloud/s :^) ). It's nice, though I could equally well see (non-canonical) air genasi who went the other way and got closer to breath as a mode of life, picking up the scent special ability. (Maybe an advanced air genasi who breathes and is descended from a blue dragon or another creature with a breath weapon might develop gust of wind or a lightning attack!)