If FlightGear was unable to download the data package (fgdata) during installation, you can download the data package by hand. Follow these steps:

1. Download the FlightGear-XXXX.X.X-data.zip package matching your FlightGear’s exact version number.
2. Extract the package somewhere on your computer. Note that the extracted package should remain available at this location after the installation to continue using FlightGear.
3. Launch FlightGear and use the “Choose folder” button to point it to the extracted data folder.