Some quotes & notes regarding Aether:
A. “Thus, once again ,,empty” space appears as endowed with physical properties, i.e., no longer as physically empty, as seemed to be the case according to Special Relativity. One can thus say that the Aether is resurrected in the General theory of Relativity, though in a more sublimated form.”
A. Einstein, Grundgedanken und Methoden der Relativitatstheorie in ihrer Entwicklung dargestellt, (Morgan Manuscript) Einstein Archives 2070.
B.“According to the general theory of relativity, space without ether is unthinkable; for in such space, not only would there be no propagation of light, but also no possibility of existence for standards of space and time (measuring rods and clocks), nor therefore any space-time intervals in the physical sense.”
A. Einstein, Aether und Relativitaetstheorie, Berlin: Verlag von J. Springer, 1920.
C. “All our attempts to make ether real failed. It revealed neither its mechanical construction nor absolute motion. Nothing remained of all the properties of the ether except that for which it was invented, i.e., its ability to transmit electromagnetic waves. Our attempts to discover the properties of the ether led to difficulties and contradictions. After such bad experiences, this is the moment to forget the ether completely and to try never to mention its name.”
The Evolution of Physics Einstein 1938
So Einstein does not say that there is no Aether, he only spoke of failure to make it real, and to give up and forget looking for it. That’s like how Newton said in 1721 that a watch could never measure time precisely, or how Ernest Rutherford said in 1933 that anyone who looked for a source of power in the transformation of the atoms was talking moonshine. The problem is discovering it.