The scary part will be if another plane disappears in a similar fashion, and then another. Then we will know for sure that the intent is to paralyze air travel. With only one disappearance it would be more likely the work of one very disturbed person.
As many have pointed out, none of the scenarios make much sense. The quote here, a little light bulb went off -- this is the most rational explanation for a very strange event.
However, I fear that perhaps the irrational has happened, and that someone took the plane down South without any rational or explainable purpose at all. It would be an intentional act either way. Systems aren't irrational....(many) humans are.