Press ' (global chat command) to display the
chat window. Type /cheatcheat to enable cheat mode. Then,
enter one of the following codes at the chat window to activate
the corresponding cheat function. Note: The codes cannot be enabled
in multi-player mode.

Code
Display game statistics /stats
Player and squad invincible /godmode
Unlimited ammunition /ammo
Flight mode /fly
Player and squad invisible /invis
Win current mission /winmission
Lose current mission /losemission