Alaska, Deep Strike: "S" rank:
Get a jet with a good FCS and equip only air to ground missiles. Fly through the canyon without destroying anything until you get to the enemy lab. Once there, destroy only the lab. If you make it in under three minutes, you will get an "S" rank for the mission.
Easy Aircraft Carrier Destroyed:
To destroy the aircraft carrier easy on the mission "Shadow of LEVIATHEN", simply equip your plane with 2 AGM88 Harm missle's. Then the aircraft carrier will be destroyed. This can be likely to be your first target.
Free Flight Mode Missions:
Get an 'S' rank on a mission to unlock it in free flight mode.