Difficult to prove a negative, but we can show that his aircraft have used non-PIA public codes for US flights recently. That makes it highly unlikely that PIA

Difficult to prove a negative, but we can show that his aircraft have used non-PIA public codes for US flights recently. That makes it highly unlikely that PIA was used on other flights in between. It also doesn’t explain why Musk’s Twitter also banned linking to ADSB Exchange and related trackers which, logically, would not have been able to track his aircraft when using PIA codes.