Cheats taken from the excellent Lega Racers FAQ by TBO

 Enter all codes in build mode as the name on the driver licence:

 FLYSKYHGH     - Fly Mode
 FSTFRWD       - Faster game
 NCHSSS        - No Chassis
 NWHLS         - No Wheels
 HIDDNKARACTRS - Unlock All Hidden Characters
 NSLWJ         - No Slow Down when not on Track
 PGLLRD        - Only Shooter Attacking Power Ups Are Available
 PGLLYLL       - Only Mine Power Ups Are Available
 PGLLGRN       - Only Turbo Power Ups Are Available
 RPCRNLY       - Only Grapple Power Ups Are Available
 LNFRRRM       - Rocket Racer Run Mirror Track
 MXPMX         - Highest Power Up Level Is ALWAYS Activated
 NDRVR         - No Driver

 NMRCHTS       - Disable ALL cheats