i was tracking 2 planes from LAX flying at almost same altitude and speed, at first i thought it was bug in FlightRadar because they overlap each other at some point.

then i notice they add different registration,

no callsign (N794RU) last flight I could find was to San Francisco 2 days ago.

when Skw5290 arrive at ASE(aspen), N794RU dissappear.

can someone explain whats the trick here?