Things like levitation and astral projection are considered to be equivalent to parlor tricks to serious practitioners of meditation.  I know levitation seems like it would be neat in theory, but it kind of misses the point.  More power to you though.

I had a boyfriend who used opiates recreationally but who also had to drop urine for probation.  Usually, 2-3 days before dropping, he would stop the opiates and flush his system with as much water as he could drink.  This method only failed him one time during the year and a half that I knew him.