There already exists examples where you don't need an actual physical material being expelled in order to have thrust. The key in this example is they are saying they have reached a force great enough to counter gravity.
The presentation is not advocating that they are violating the 3rd law. Most people's argument here boils down to 'but but , thrust, the 3rd law, duh, I read an engineering book in school once'. And dismiss this out of hand.
He provides a prototype, at least give it the same attention as the high temperature superconductor and replicate it, then provide some explanation where the force is coming from that negates any benefit. Like find if there is some static charge at play that is causing the measurement error and would make it useless.