Simviation Forums

Can someone tell me why some models allow customized tail numbers but others don't?

The ability to change the visible tail number has to be built into the model. It is built into all default aircraft. On most add-on aircraft you cannot. Many are built to represent real registered aircraft, but in the end it's up to the author.

If you really want a different tail number, you could change them by editing the appropriate texture. You can of course change the reg. used by ATC, in the Details window when selecting the aircraft.