This is really cool. Have you considered showing the aircraft model/type? Since the ICAO24 is already available, a lookup could add it.
Modelling only the most common aircraft types sounds like a good approach.
With the ICAO type code, maybe you could group aircraft (wide-body / narrow-body / regional / cargo) to provide an accurate visual fallback when a specific 3D model isn’t available. Also, a slightly different shade for the generic aircraft could help signal that it’s just a placeholder rather than a real model.
The altitude seems a little off - is it supposed to be to scale? Some aircraft flying around 1,000-3,000 ft looked closer to FL20 from my experience as a passenger and pilot.