The concept of Lorentz invariance is basic postulate of special relativity theory and one of most deeply misunderstood concepts of Aether theory, being considered incompatible with relativity in general. The true is, the light speed invariance can be derived easily from Maxwell's Aether theory of light, based on transversal wave spreading. As I demonstrated already, the ability of luminiferous Aether to spread the light of whatever energy density effectively implies the very dense environment and the transversal character of energy spreading (which is required for casual spreading of information) in it, because the sparse Aether cannot spread the EM waves of whatever energy density. Therefore the famous Michelson-Morley experiment (MMX) shouldn't be used for disapproval of Aether theory - but for effective confirmation of it, instead. It shoud be noted, with contrary to widespread belief the negative result of MMX cannot serve as a confirmation of relativity, because the light speed invariance isn't theorem, but a postulate (i.e. sort of axiomatic tautology) in special relativity theory.
Another general source of Aether misunderstanding is the common belief, the concept of particle environment isn't compatible with light speed invariance and the relativistic physics in general. This is nonsense, because the common interpretation of Galileo transform isn't compatible with relativistic Lorentz transform. The spreading of sound wave in air cannot be considered as analogy of light spreading in vacuum, until we consider the sound wave as the only source of information including the time and distance intervals measurement, i.e. by the same way, like during light spreading in vacuum. The common understanding of wave spreading in particle medium usually involves at least TWO kind of waves (the light wave, used for time/distance measurement and the studied/observed wave itself), while during light spreading in vacuum the only kind of energy spreading can be considered (the light wave serves here both as the subject of observation, both the mean of observation). This general inconsistency in experiment interpretation leads to the (false) conclusion, the Newtonian mechanics and the invariance of energy wave speed in particle environment is incompatible with the light speed invariance (and the relativity theory in general). As we can see, it's just a result of fundamental inconsistency of experimental arrangement, instead. Therefore MMX cannot give a positive result, simply because it’s virtually impossible to detect every environment just by it’s waves. If some particle is serving for wave spreading, it cannot be observed just by this wave and nothing very strange is about. No object can serve as a mean of it’s own observation and the inner and outer perspectives cannot be mixed.
The similar mistake consists in widespread belief, the absence of reference frame excludes the existence of luminiferous Aether, the particle environment in general. In fact, no particle in such environment cannot serve as an subject of observation and the mean of observation at the same time, therefore the absence of reference frame is the natural consequence of energy wave spreading inside of such environment, if we make sure, the same kind of wave is serving as object and mean of observation, i.e. by the same way, like during light spreading in vacuum. As the waves in particle environment are mixture of longitudinal and transversal waves in general, we can follow the above rule and the absence of reference frame most efficiently at the cases, when only transversal wave spreading prevails - for example at the case of capillary waves spreading along water surface, which is driven by surface tension (nearly) completely. With respect of these waves the water surface is behaving like thin elastic membrane with (nearly) no underwater (motion/reference frame) at all - so we can see clearly, the transversal wave spreading in particle environment is really background independent and no additional postulates are required to consider here.
By analogous way, we cannot observe the water surface by using of water waves and nothing very strange is about. The water surface will always appear as a void, empty space from surface waves perspective, because it just serves as an environment for these waves. The common observation of water waves by light waves cannot serve as a direct analogy of observation of light waves by using waves in vacuum, simply because in vacuum only one kind of waves can be always involved in experiment - the waves of light. So here’s nothing strange about different results of "classical physics" experiments, which were made in different arrangement(s). This doesn’t mean of course, the classical mechanics differs from reality conceptually - it just means, we aren’t observing wave phenomena by the same way, like during experiments in vacuum - that’s all. The Lorentz invariance (symmetry) of Aether is valid as long the transversal character of wave spreading is retained. Because the transversal wave spreading is the only causal way of information spreading considered for human creatures, the Lorentz invariance follows automatically from unitary time arrow and vice-versa: the quantum uncertainty related to multiplicity of time arrows and longitudinal energy wave spreading is equivalent to Lorentz symmetry violation.
Note that the transversal wave is the case, where the energy spreads by the slowest speed through such environment, i.e. here's a minimum of the celerity / wavelength dependence. This makes the environment as large, as possible from internal observer perspective - so we can say, the Universe appears so large for us just because of transversal character of light spreading. It's somewhat surprising, these fundamental connections were revealed after nearly four hundred years after postulation of particle luminiferous Aether concept by R. Descartes (1644) and Ch. Huygens (1678) on behalf of positivistic, ad-hoced (i.e. belief based) consideration of relativistic postulates."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)