Airforce Delta Cheat Codes for Dreamcast

Pass through objects
Pause the game before your plane hits an object. Then, press B + Y to change camera angles. Then resume the game and your plane will pass through the object.
Full replay screen
During a replay, hold X + Y to remove the text from the screen.

Special options
Complete all twenty missions on the normal difficulty setting to unlock a "Special" selection on the options menu. The new options allow infinite missiles and the HUD display to be removed.

Bonus airplanes
Complete all twenty missions to unlock the following airplanes: Sea Harrier, AV-8B Harrier II, F/A-18C Hornet, F-15E Strike Eagle, Su-27B Flanker, Su-34 Platypus, S-37 Berkut, MiG-1.44 MFI.

EE Lightning
Beat the game on hard to earn one more plane in the shopping screen, the EE Lighting.

Quick Money
During level 1, on any difficulty shoot down the 3 targets. Make sure to use guns not missiles. It gives 135,000 per plane versus the usual 60 or so thousand.