No, according to modern physics, Planck's electromagnetic standing waves, which are fundamental units of energy known as quanta or photons, are not formed by the motion of an ether. The concept of the ether was proposed in the 19th century as a hypothetical medium that was thought to permeate all space and serve as a medium for the propagation of electromagnetic waves.
However, with the development of special relativity and subsequent experimental observations, the concept of the ether fell out of favor in modern physics. The theory of special relativity, formulated by Albert Einstein, demonstrated that the speed of light is constant in all inertial reference frames and does not require the presence of an ether to propagate.
In the framework of quantum mechanics, electromagnetic waves, including the quantized electromagnetic waves described by Planck's theory, are understood as fundamental particles called photons. Photons are not composed of any material medium but rather exist as discrete packets of energy and momentum that exhibit wave-particle duality.
According to the modern understanding of physics, there is no need for an ether to explain the formation or propagation of electromagnetic waves, including the discrete energy levels described by Planck's theory. The concept of the ether has been largely replaced by more comprehensive and accurate models of the fundamental interactions of particles and fields in the framework of quantum field theory and the theory of relativity.