There is a theory that the origin of the idea of witches flying with their brooms is based in a ritual involving a psychoactive drug trip.[1] The witches would prepare a flying ointment to aid them in their journey. There are many recipes for this ointment all having a base of either Atropa belladonna or Mandragora officinarum, both highly psychoactive drugs producing visions and encouraging astral projection.[2] Some speculate the ointment was applied to the end of the Besom and administered vaginally.[citation needed] Witches mounted broomsticks and would leap around the fields, hallucinating with the aid of the flying ointment, in order to "teach the crops how high to grow". The ointment would give them hallucinations, which made them believe that they flew distances.[3]

http://en.wikipedia.org/wiki/Besom