She can change to either of her two forms, the feline or avian one without the necklace---although it's harder, and is more painful.  Yet the avian form is relatively useless. Without the antigravity effect of the necklace, there's no way a reasonable wingspan would allow her to fly.

Of course, antigravity---now THAT would revolutionaize mankind. With that secret, a revolution similar to the Industrial Revolution would have happened. Its value is---incalculable.

It also would go a long way to proving the existence of both the Next Level and their alien enemies....the Zha'Tahn.

Who developed the necklace?   Where do the other artifacts the Next Level use come from?

You'll discover more---next time.