Basic help resources on FlightGear:
Short reference including key codes (also available as PDF)
Guide to joystick and keyboard configuration
Information for power users:
Guide for the Local Weather Package
Getting more help:
Additional documentation can be found in the Docs/ folder.
Since FGFS has a brisk pace of development, some information may be inaccurate.
More information and help is available on the FlightGear Forum and FlightGear Wiki.
Get new versions from the website at www.flightgear.org for free.