Press ~ during game play in single-player mode, then activate the following cheats by entering the corresponding codes:

CHEAT FUNCTION - CHEAT CODE
Invincibility1 - aiCheats.code Tobias.Karlsson
Kill enemy bots - aiCheats.code Jonathan.Gustavsson
Kill bots - aiCheats.code Thomas.Skoldenborg
Bots cheat - aiCheats.code BotsCanCheatToo
Toggle AI statistics - aiCheats.code TheAllSeeingEyeOfTheAIProgammer
New spawn location - aiCheats.code WalkingIsWayTooTiresome
Super jumps - aiCheats.code moonwall
Automatic loss - aiCheats.code Hitler.Rules

Note 1: Activating this code may take you down to one flag. Your health will never decrease, even when in a vehicle. Enter the cheat correctly, then do it incorrectly so that you can replay the level with all of your flags and still have invincibility.

Play the Heledoorn map and go to the position (spawn point) to the south of the airfield, playing as British. Go to the large white building and get on top of it. This is done easiest by using the mini plane. Look down and get above the "bunker building". Enable the "Invincibility" code. Keep looking down and fall to the ledge below. Keep looking down; this works best if you look almost straight down, but do not use the parachute. Instead, when you hit the ledge, the game still thinks that you are falling and will soon "crap your pants". However, if you look upwards slightly (not level or up or it will end), you can do this until you get to the water.