At the Title screen menu, hold R1+L2 on controller 2 and rapidly press the Select button 20 times; you'll hear a signal to comfirm the code. Now you'll find two new planes at the "Airplane Select" screen: an F-16 and a stealth fighter.
press and hold R1 and L2 on controller two, then tap the SELECT button 20 times. You have to be quick, or else the rankings will start. An electronic noise will sound if you did it right. You can find the new planes on the plane select screen.
