I wouldn't know. The person I replied to claimed that it was "private information of individuals". If it's public info by law then referring to it as private seems very misleading, wouldn't you say?
The aircraft tracking data itself is public, but what's not public is the information which links the temporary aircraft identifier to its owner when the owner is using that privacy program, which is the case for Elon: https://twitter.com/elonmusk/status/1603803508087537665
That source is a reply by Musk confirming a statement by another person (https://twitter.com/Timcast/status/1603748611896283137?s=20&...) commenting about Musk being enrolled in the PIA program. That statement also has a link back to the creator of the tracker themselves also admitting Musk's plane(s) are/were in PIA but they figured out how to track it/them anyway.