Troubleshooting Invisible Aircraft added to MSFS Community Folder

First and foremost, let me say I understand your frustration. Adding aircraft to the Community folder and not seeing them can be a vexing issue. Let's break it down step by step.

1. Proper Extraction of Aircraft Files:
Ensure that when you're extracting your aircraft files, they aren't nested too deeply. Sometimes, aircraft come in multiple folders deep and the actual aircraft content should only be one level deep within the Community folder.

2. Folder Structure:
The correct folder structure is vital. The main folder of the aircraft should contain the 'manifest.json' and 'layout.json' files directly inside. If these files are buried in another subfolder, the sim won't recognize the aircraft.

3. Check the Content Manager:
Within Microsoft Flight Simulator, navigate to the Profile and then Content Manager. Ensure the aircraft you've added appears here and is enabled.

4. Compatibility Check:
Although you're using Microsoft Flight Simulator, some aircraft might have been designed for earlier versions or different platforms. Always ensure the aircraft is compatible with the version you're using.

5. Conflicting Mods:
Sometimes, other mods or add-ons can cause conflicts. If you've recently added any other mods, consider temporarily disabling them to see if it resolves the issue.

6. Clean Start:
Before resorting to a full reinstall, try removing all content from the Community folder and adding only the problematic aircraft. If it appears, there might be an issue with another mod or add-on.

Reinstalling the Flight Simulator:
I'd consider this a last resort, especially given the size of the installation (10 CD's, as you mentioned). If you've tried the above steps and are still facing problems, then a reinstall could be the solution. Before doing so, back up your settings and other custom content.

From my knowledge, a reinstall has solved numerous issues for users in the past, but it's always wise to troubleshoot beforehand.

Lastly, if you could provide a bit more detail about the aircraft in question and where you sourced it from, I could potentially offer more specific advice.

I sincerely hope these steps can help you solve the problem. Happy flying!