The concepts of  electromagnetic fields and waves  were born 800 with Faraday, Hertz and Maxwell, as conditions of the ether. 
Then at the beginning of '900, arguing that the Michelson& Morley experiment had shown that the ether does not exist, other scientists, suppressed the ether and established the concept of space with nothing in it. 
However, removing the ether, they left the fields and waves electromagnetics, which have become so  - conditions of nothingness - .
That the experiment of M & M had not shown just anything had already explained by Fitzgerald and Lorentz immediately after the experiment itself, but books citing this explanation were a small minority; then it has gone on for nearly a century, ignoring, or not accepting this explanation. Only at the end of the '900 the truth emerged and we've come to accept what said Fitzgerald and Lorentz to the end of '800.
Let us now consider the fields and waves e.l.m., but the discussion can be extended well to the waves and gravitational fields, the curvature of space, and so on. 
These physical entities exist in empty space, where, who does not believe in the ether argues that there's nothing. But there are still the fields and the waves. 
Now a physical entity to exist needs of something which, with its state, define it and identify it. 
What is the physical support to these physical entities? 
Who does not believe in the ether that exists in space, answers: - nothing, in the empty space can exist the fields and waves without support at all, and just so..
And if there is nothing what is it that oscillates? Someone said: a wave. 
A wave of what? if there is  nothing? New answer: there is a wave and that's enough!
But then, with these assumptions, the fields and the waves are just abstract concepts, made of nothingness. 
And what is the difference between a space where there are fields and waves, and another space where the fields and waves are null? 
If you really believe that into the "empty" there was nothing, there could be no difference, because the state of nothingness can not change. 
We can not have a nothingness here different from a nothingness that there is a little further.  The "Nothingness" can not change!  
So it is necessary to underline that without ether in space, fields and waves, no longer having any physical support, they become just abstract entities. 
But they produce real effects on the matter: forces, induced tensions, etc. .. 
And if they are made of nothingness, how do these abstract entities interact with matter and produce real effects?
These are all questions who does not believe in the ether must ask himself. 
Then there is also the energy associated with the fields and waves. 
We know that in order to have the energy you need to have a physical system in a defined state: a compressed gas, a hot mass, a compressed spring, a charged capacitor, a mass rotating or translating, a body lifted above the Earth, and so on. 
Now where there is a field there is also the energy associated with the field, which was supplied by the generator that powers the source of the field. 
Take for example a inductance without core in steady state conditions. 
The energy contained in the volume of space where there is its magnetic field is 

E = 1/2 LI ^ 2

If the inductance is in the empty space, where, according to who does not believe in the ether, there's nothing, what, with its state, defines this energy? 
The nothingness? 
Than we have a cubic meter of nothingness with a joule of energy inside?!? 
According to those who do not believe in the ether, in space there would be energy like state of nothing. And not like the state of something that defines it. 
While those who believe in the ether can define this energy with the state assumes by the ether in the presence of a field.
Then the empty space without ether is very inconsistent. 
Briefly: all the real physical properties that have fields and waves can not be based on nothingness!
For all these reasons the supporters of the ether are becoming more numerous. 
Of course it is also difficult to provide a model of ether consistent with the physical reality. 
The old models, including the luminiferous ether, were not consistent with reality
 because they considered the particles of matter such as foreign bodies respect to the ether. 

An interesting new model of ether is described in: 

http://www.ricercaetereperduto.it 

or in: 

- new ether and the new physics -

which can be found on Google.

Best regards