Unlock the following Weapon Packs by beating the corresponding bonus objectives on the specified difficulties:

WEAPON PACK - HOW TO UNLOCK
Air Attack (for MiG-27 Flogger V2) - Mission 1.1 on the Pilot difficulty setting.
Circuit Breaker (for F-117 Nighthawk) - Mission 2.2 on the Ace difficulty setting.
Circuit Breaker (for F-22 Raptor V2) - Mission 2.4 on the Ace difficulty setting.
Cluster Bomber (for F-16 Falcon V2) - Mission 1.3 on the Pilot difficulty setting.
Long Ranger (for F-15 Eagle V2) - Mission 2.1 on the Rookie difficulty setting.
Multirole (for SU-27 Flanker V2) - Mission 2.3 on the Ace difficulty setting.
Multirole (for Mig-31 Foxhound V2) - Mission 1.2 on the Rookie difficulty setting.
Naval Fighter (for MiG-29 Fulcrum V3) - Mission 2.4 on the Rookie difficulty setting.
Rocket Attack (for MiG-29 Fulcrum V2) - Mission 1.3 on the Rookie difficulty setting.

To unlock the SR-71 Blackbird, beat the Pilot bonus objective on the last mission.

Unlock the following Aircraft by beating the corresponding bonus objectives on the specified difficulties:

AIRCRAFT - HOW TO UNLOCK
F-15 Eagle V1 - Mission 1.3 on the Rookie difficulty setting.
F-15 Eagle V2 - Mission 2.3 on the Pilot difficulty setting.
F-16 Falcon V1 - Mission 1.3 on the Rookie difficulty setting.
F-16 Falcon V2 - Mission 2.1 on the Pilot difficulty setting.
M-27 Flogger V2 - Mission 1.2 on the Pilot difficulty setting.
MiG-27 Flogger - Mission 1.1 on the Ace difficulty setting.
MiG-29 Fulcrum V2 - Mission 2.3 on the Rookie difficulty setting.
MiG-31 Foxhound V1 - Mission 1.3 on the Ace difficulty setting.
MiG-31 Foxhound V2 - Mission 2.1 on the Ace difficulty setting.
T-45 GOSHAWK - Mission 1.1 on the Rookie difficulty setting.
Yak-141 Freestyle - Mission 1.2 on the Ace difficulty setting.

Complete the Ace bonus objective in the final mission to unlock the SR-71 Blackbird's fourth weapon pack. This weapon pack includes the game's super weapon, the A-SLAMR. The A-SLAMR does not recharge after it is fired. Note: To unlock the SR-71 Blackbird plane and "The Big One" weapon pack at the same time under the Ace difficulty setting, complete both of the required bonus objectives.

When landing your plane, look for blue rings floating near where you are landing. Use your airbrakes to slow down your plane and fly through the blue rings. This will cause your landing gear to deploy.