With the latest next (by download_and_compile.sh), the launcher stops after selecting a plane and a black screen replaces it.
In the console, we find these errors.

My compilation from October 28 is, as for it, correct.
My distro : Linux mint 22 Wilma
Is your FGData up-to-date?
Yes, of course, and the errors occurs with all planes, even with the UFO.
The problem comes from the file ".fgfs/FlightGear/FlightGear.ini" which is not updated.
If I replace the old ini file (28/10/2024) by the ini file from the latest compilation, the error persits but the loader works and it doesn't prevent the old compilation from working as well.
I'm confused - we don't create the .ini file as part of compilation, instead we create it on first run, if it doesn't exist. Can you attach the non-working .ini file here?
Here is the FlightGear.ini file (28/10/2024 (www.mediafire.com)
Trying to debug the crash, it's weird.
The warnings in the console (Unknown key ....) are unrelared BTW.
It looks like the issue might be changing encodings. Can you delete just the aircraft-cache part (which is most of the file) and see what happens?
By deleting "aircraft-cache" from FlightGear.ini, it is rebuilt when launching Fg, but with the same errors :
Unknown key 'Shift-Esc'
Unknown key 'Shift-F10'
Unknown key 'Ctrl-R'
Unknown key 'Ctrl-M'
The launcher does not crash and the plane selected is loaded.
The error
is only shown for certain aircraft, e.g. 737-800.
Okay, it's something in the aircraft cache then, interesting. Thanks for confirming.