In fact, this magic fabric cannot eliminate air resistance. If it did, the swimmers would not need to put in any effort beyond diving in at the start, because in the absence of resistance, objects keep moving at a constant velocity, like the planets do. They could also not stop until they hit the wall at the other end, at rather dangerous speeds.
If there is any air resistance, which there must be, the elephant will eventually reach what is known as terminal velocity. This is where the upward force of air resistance, which increases with velocity, balances the downward pull of gravity, and so the elephant stops accelerating. Its impact velocity is therefore limited to a certain maximum determined by how aerodynamic the elephant is; and elephants were not designed to be aerodynamic!
Sorry to be such a spoil-sport! Great idea though ;)