Do you have the same issue if you follow the OP’s steps to reproduce it?
• Yes
Provide extra information to complete the original description of the issue:
• Load any plane and change the ID. The custom ID / tail number is not retained for the flight. In MSFS2020 the tail number could be set and would persist until changed. In 2024 even if you set it each flight it reverts to the default tail number when the flight starts.
If relevant, provide additional screenshots/video:
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