Doing aerials is not to be taken lightly. First, you need to decide what type of aerials you want to learn. Do some research using old movies to find out what style and period of aerials you're interested in before wasting time and money as well as risking life and limb learning a style of aerials that doesn't fit your dancing or that you won't enjoy doing. If you dance competitively make sure that the aerials you're learning are stylistically consistent with your dance style and that the competition rules permit the aerials you're learning. If someone is teaching you aerials, watch them teach a class before signing up.
Sand is softer than concrete, but it provides an uneven shifting base.
Also, falling on your head hurts your neck even on sand. I personally believe that nearly every one of the aerials can be taught with hands-on spotting. Copyright 1990 Bob Thomas. No reprinting without permission.