F-15 and Mao-Mao:
Press C-Left, C-Down, C-Right, C-Up, C-Left, C-Right, C-Down when "Press Start" appears on the opening screen. A hidden F-15 with a female pilot (Mao Mao) can now be accessed.

Level select:
Press Up, C-Down, Left, C-Right, Down, C-Up, Right, C-Left, L, R, Z during the opening sequence when the fighters are in flight. A sound will confirm correct code entry. Note: The code must be entered before the title screen appears.

Alternate plane color:
Press R at the plane selection screen in main game, practice or boss attack modes. For death match mode, hold R while selecting one of the four default planes.

Bonus missions:
Complete the following tasks to unlock each bonus mission.

Air Docking: Accumulate a very high score.
Shuttle Defense: Quickly complete all the levels before the "Desert" level.
Goliath Defense: Successfully complete the first two bonus levels.
Space: Successfully complete all regular missions and "Air Docking", "Shuttle Defense", and "Goliath Defense" before reaching the "Ice Cave" level. Successfully complete the "Ice Cave" level to unlock the "Space" level.

F-14 super-attack:
Fire the special weapon followed by a missile and then chaff while flying the F-14. Five Tomahawks and four heat-seekers will then be fired.

Spanky:
Find and successfully compete all bonus missions to unlock Spanky, the second hidden pilot.

Fly enemy planes in deathmatch mode:
A new enemy plane will be available in deathmatch mode for each level completed during game play. A total of six enemy planes may be enabled.

Unlimited continues:
Before reaching one credit remaining, reset the game and continue from the menu that immediately follows the title screen. The game will resume with the same number of credits that were available when the current stage was started.

Hints:

Defeating the Boss on level 3:
There is a way to defeat the Boss on the level 3 (with all the bombers) without getting hurt. If possible, clear out some of the numerous bombers. Get to the highest elevation possible. When your fighter is above the Boss on your radar, dive down and fire missiles and the gun. Done correctly, the Boss will not shoot back until your fighter gets too close. Repeat this procedure until he is defeated.

Alternatively, after clearing out some of the numerous bombers climb t to the highest elevation possible. When you fighter is above the Boss on your radar, dive down and wait until your fighter is locked on the Boss. Fire the missiles and go through the Boss. Your fighter should explode. When the game restarts the Boss will still have the damage inflicted by your attack. Repeat the steps until the Boss is defeated.

Easy multi-player kills:
Select the F-15 (if available) in multi-player mode. Use the special weapon as soon as the dogfight begins. This should completely destroy your opponents in one shot. For a better chance, place enable infinite specials in the settings.

Ice Cave shortcut:
Fly down the cave until it widens. Then turn around and fly back. Pass through the gray bars and continue until the Boss appears.