Enter the following cheat codes at the code entry screen / stage:

Cheat Code - Effect

FRHS - Rapid Fire
NSTNT - Speed Shots
JMPTT - Level Select
TWFSTD - Double Bux
GRTD - Every Movie
VRLRDS - Overlords
DNGDM - Invulnerable
TWLVCHTS - All Cheats
ZPPY - Fast Planes
HMMR - Bigger Guns
NDBMBS - Dual Fire
DZZY - Spin Shots
MRRMR - Thick Armor
SMSHNG - Plane Wins
NDCSN - Switch Planes
QD - Biggest Guns
SNKY - Ghost Mode
DH - Top Gun
SPRLZY - Every Level/Cheat Unlocked
WNNNGS - Extra 10 Bux
WNRLFST - Valhalla
BXDRW - Show Boxes
WYPNT - Waypoints
PYRS - Weapon Up At 3
SCRW - Shields On Roll