No, they would have to qualify as transportation carriers. They are still subject to the NLRB.

Under US law, the NLRB excludes employers subject to the Railway Labor Act. xAI and X would need their own classification. It does not propagate automatically through ownership or mergers.

https://www.jdsupra.com/legalnews/nlrb-general-counsel-wants...

https://www.hunton.com/hunton-employment-labor-perspectives/...

They did not merge into a single entity, they continue to be separate entities. SpaceX owns xAI, and xAI in turn owns X.