Invincibility
Pause the game, then hold LT and quickly press X, Y(2), X. Then, hold RT and quickly press Y, X(2), Y. Repeat the code to disable its effect.
All Campaign Missions and Planes
At the main menu, hold LT + RT and quickly press X, LB, RB, Y(2), RB, LB, X to unlock all campaign missions and planes.
Increased Damage by Weapons
Pause the game, then hold LT and quickly press LB(2), RB. Then, hold RT and quickly press RB(2), LB. Repeat the code to disable its effect.