Uuuh well no it doesn't, not in the way "they" mean at least, though I'm not entirely sure who "they" are.
Let me just give you a quick rundown on what this whole "aether" business is and how it's related to magic. In ancient Greek cosmology, aether was a word for the "stuff" of the upper sky. Later, in the 19th century, after having understood the mechanism of sound as waves in air, physicists were working out what light is, and posited it (light) to be waves in a more "subtle" medium than air, which they called aether.
It used to be the "state of science" for a while, until physics figured out about electromagnetism and photons, and so the idea of a material medium that resonates carrying light ("aether") was abandoned as obsolete. It was removed from textbooks because science found a
better explanation for how light "works". (Better as in more in line with how light actually behaves.)
Here's where the confusion comes in. We have an ancient word connected with the upper sky ("outer spheres" in geocentric astrology), and an obsolete concept from 19th century physics... Western magic has an ancient and deep connection with both ancient Greek cultural heritage and with astrology, and the magical practicioners of the 19th and early 20th century were very much into adopting scientific terms... so of course they used the term "aether" to mean a number of things, typically related to some kind of "subtle" or "astral matter" , or energy, or something. What was exactly meant by it depends entirely on the person and tradition using it.
So no, there is no one unambiguous thing called "aether", and there was no conspiracy to hide it from physics textbooks.