Detailed cockpits: civilian: control lever, and flight display. And yaw pedals
Jet: holographic sight, control lever, flight display, and yaw pedals.

Bomb sight: shows where sploshins happen.

Hellfire missile/bomb: locks on aircraft, ground vehicles, and can be used as a dumb bomb. Splits into smaller multiple explosions causing bigger splash damage.

Blimp parts: fire proof ballon cloth, and ability to change fuselage into a helium filled fuselage and blimp cockpit: joystick and flight display.
And blimp fins.
I know this is a lot to as for, but probably the blimp parts and detailed cockpits would be best. :D