I was wondering what are the benefits of braking in the air, or what is the purpose?
You can use your rear brake to drop your front end. This is an advanced move, and you should use it with caution.
It’s better, most of the time, to control the bike’s attitude with your arms. Stay balanced over your pedals, and let the bike rotate below you. Click on the photo series at right. –>>
DO NOT use your front brake in the air.
Cool. Have fun, and stay on your feet!