The whole hovercat thing is a prime example of bad science. We start with two premises: A cat always lands on its feet, and toast always lands butter side down. If the cat-toast combination doesn't land, this violates both original premises: If a cat doesn't land, then it doesn't land on its feet, and if the toast doesn't land, then it doesn't land butter side down. What we need is a system whereby both cat and toast do, in fact, land, and in the required orientation. The obvious possibility that presents itself is that the cat lands on its feet, and then immediately proceeds to roll over onto its back, thereby smearing butter on the linoleum.
Time travels in divers paces with divers persons.
--As You Like It, III:ii:328