Air Guitar is a type of dance. You basically dance about on stage, playing an invisible guitar. Very fun and it provides good exercise.
I am a guy who likes to work out. I do lots of turbulence training and interval training. Cardio like jogging and biking burns lots of fat too, but dancing is the most fun way to sweat and get your heart pumping.
Air guitar is a dance style that is unique and fun to do. There is actually no guitar involved and you are free to do whatever you like. This guy in this video is really rocking out with his air guitar!