There is a point made by Bell in the remarkable paper "How to teach special relativity" that it is useful to teach, together with the usual Minkowski spacetime interpretation, also the classical Lorentz ether interpretation. I think this should include also an introduction into the Lorentz ether interpretation of the Einstein equations of GR, as I have argued in my paper "About an ether interpretation for the Einstein equations of general relativity". I think, this deserves to be worked out, and I have started such an attempt to teach relativity by teaching above interpretations. The actual version of this introduction is: " Lorentz Ether or Spacetime? An Introduction to Relativity" [pdf]". (The part about special relativity [html] is available separately.)
An aspect of the "twin paradox" is examined: It is wrong that it is somehow the acceleration which creates time dilation.
Here I will collect some points where I'm critical of some aspects of relativistic mainstream physics. To clarify: special as well as general relativity have been, without any doubt, great advances of physics in comparison with pre-relativistic theories. And even if my own ether theory of gravity will be successful, this status will not be questioned: Instead, the Einstein equations of General Relativity would remain the natural limit \(\Xi,\Upsilon\to 0\) of my own theory. This would define an ether interpretation of the Einstein equations of General Relativity.