Air characters use the air, lightning, and more to try to save the day.
Sonic Boom is currently the only widely available Air character available. Whirlwind is a Target exclusive in North America, and the other two are currently unreleased.
Sonic Boom screams and hatches eggs. The scream is her primary attack, while the eggs spawn baby Sonic Booms that attack nearby enemies. They can even be powered up by her scream. I don't know what this says about Skylanders' representation of women...
Whirlwind is a unicorn who can emit rainbows from her horn. She can also flap her wings and blow wind at enemies. Basically, she's the closest thing to The Last Unicorn that Skylanders has.
Lightning Rod uses the power of thunder to harm those who cross him. He kind of looks like a stylized Zeus chilling in his cloud with his beard and golden gauntlets.
Warnado is a spiky-shelled turtle who can use the power of wind to summon tornadoes to help him fight off enemies.