From the Main Menu (the screen where you choose
between Arcade mode and N.Gen Mode) enter the following code

R1,L1,R1,R2,L2,R2,L2,L1
then access Arcade mode and enjoy.
This will unlock the next three chamionships
and the other three levels of airplanes.

From the main menu screen (Yup, the one where you
select between Arcade or N.GEN modes)enter the
following code to give you self a very nice
assortment of airplanes in N.Gen mode.

R1,R2,L1,L2,L2,L1,R2,R1
This code will unlock a handful of aircraft and give them to you. With these aircraft you can win almost any race and rack up the money. Or, just enter the $400 million code.

From the main menu
enter the following code to
gain access to a butt-load of money.

R2,L2,R2,L1,R2,R1,R2,L1
Use the money in N.Gen mode to buy more planes
and upgrades.