This is a Windows issue. By default, Windows limits file paths to 260 characters. You can disable this limit by modifying the system registry (not as scary as it sounds). Tutorials for how to do so can easily be found with a Google (or Bing) search.
This problem usually occurs when a subfolder was created during extraction of the archive. You can check this by opening the mod folder in your Community directory. It should contain a
layout.json and a
manifest.json file. If it only contains a subfolder, copy the contents of that one level up, until the beforementioned criteria are met.
This is a known simulator issue. It does however only have an optical effect and the plane continues through that glitch without any negative effects.
If the answers on this page can not help you solve your problem, you can always pose your questions on our Discord server below.
Please do however read the Guides extensively beforehand.