"to show how cats reach terminal velocity by making themselves into little parachutes"

It is widely thought that cats have a non-fatal terminal velocity, as they orientate themselves like flying squirrels.  Stories abound of cats surviving very high falls, including one that was dropped from a light aircraft at 800 feet by a particularly repellent amateur experimenter.

However cats ARE frequently badly injured by big falls.  Dropping cats off roofs is cruel, regardless of their survival chances.