Many of the aircraft created by Project Opensky were designed for Flight Simulator 2004, however will work in Flight Simulator X with some tweaking.
To get it working, install the aircraft as normal. Once installed, you’ll need to replace the panel and sound folder with that of a default aircraft.
Example: Boeing 737-800
1. Install Aircraft
2. Delete panel and sound folders
3. Copy the panel and sound folders from Default 737-800
4. Paste into Project Opensky aircraft folder.