As per the article:
Flights with a rail alternative that takes less than two and a half hours will no longer be allowed, “except in cases of connection with hub airports that link with international routes”.
The only trip that I know of that takes less than 2.5 hs by train is Madrid-Barcelona and Madrid-Valencia . But Madrid is an international hub with connections to most of the international routes. So, my thinking is that this would not apply. It might only make sense for private flights, which are already very minor, AFAIK.
Again, smokescreen law, from smokescreen leftist party.