During play, pause the game and enter the following cheats:

slallcheats   Activate all cheats
sllottery     +50000 EUR and 1 Licence 
slroads       Open all roads  
slmap         All hidden items visible on the map 
slrepair      [Backspace] for free repair 
slrecover     [Ctrl][5] for free recovery 
slfillup      Unlimited fuel 
minesoff      No mines 
slturbine     Activates better thrusting:
                [Ctrl][1] More forward thrust 
                [Ctrl][2] More backward thrust 
                [Ctrl][3] More thrust upturn 
                [Ctrl][4] More thrust downturn
   
   

Thanks to Revolution readers Oliver Sandercock, tango and RoadRunnah!