According to Ian Darwin Edwards, a scottish researcher, the legend of Santa Claus' Flying sleigh and reindeers originated from drug hallucinations of the inhabitants of Lapland.

According to Edwards, the people living in northern Finland (Lapland) were feeding their reindeers poisonous mushrooms and after that drank the reindeer's urine, thus getting the hallucinogenic substances into their own system. And therefore got into a state comparable to being under the effects of LSD.

In this state, they thought it possible for them to fly with their reindeers. Later in their stories, the flying sleigh appeared behind the reindeers.

Edwards also suspects, that in their hallucinogenic state, the laplanders also saw the person, we nowadays know as the Santa Claus.