The mission codes are:

Code     Mission No.        Code      Mission No.

AAAA         1              LOCK           6
PLAN         2              HAND	   7
ALFA         3              FLEA           8
BELL         4              LIFE           9
NINE         5

Landing upside-down:

How About an Upside-Down Landing? In Level 6, you land and take-off from air strips. Try doing a barrel-roll (Pressing Option 2 and turn left or right), and then hold the plane upside-down, while pressing Up over and airstrip (to land). You will then land upside-down, the cockpit opens from the fuel tank, and you take off backwards!

Bonus points:

For bonus points, hit your afterburniners as you enter the canyons on level BELL. The Gutsy Bonus will give you 30,000 points ("You've got guts!"). When you're in the canyons fire your afterburners for 65,000 poins (Lunatic Bonus) "You're crazy!!" The points are added when you land -- but if you do both, it will only display the Lunatic Bonus, but you get points for both. (A good place for the second bonus is right before you enter the second set of canyons)