Deadly Skies Codes -

Level select:
Press L2, L1, Triangle, Up at the title screen.

F-19:
Press Up, Down, R1, Circle, Square, Left, L1 at the plane selection screen.

F-117:
Press Square, R1, R2, Square, Up, Square, L2 at the plane selection screen.

Laser gun:
Press Left, Up, Right, Triangle, Select, Left, Right, X during game play.

More guided missiles:
Press Right, Down, Left, Up, Triangle, Select, R1, R2, X during game play.

Unlimited S skill:
Press Right, Down, Left, Up, Triangle, Select, Left, Right, X during game play.

Start at Boss level in two player mode:
Press L2, L1, Square, Up at the versus mode selection screen.

Start at second Boss level in two player mode:
Press L2, L1, Square, Down at the versus mode selection screen.