Thus the only public source is ADSBExchange because it uses croudsourced data. Imagine that people put crowdsourced license place readers on their private property and then through a made an aggregate of this data on the public movements over every car available (and charged commercial users.)

That would be quite problematic for personal privacy.

ADSBExchange isn't quite the same as that since airplane movement is less granular and thus less privacy is lost. Also, the people who use private jets tend to be rich and powerful, so there's an aspect of "punching up" here that is not present in the crowdsourced car movement analogy. Still, I don't think the privacy considerations here are as cut and dry as the people who are claiming "it's public data, what's the problem?" are making it out to be.