g suit   A suit worn by pilots to counter the physiological
    effects of high g  forces.
GBU   Guided Bomb Unit -- "smart" bomb.
general strike package    A selection of planes designated
    to attack a target.
glareshield   The screen onto which a head-up display is
    projected.
glide path   The path of descent to landing.
green shirt   An aircraft carrier deckhand whose duties
    involve readying aircraft for launch, securing them to
    the catapult. 
gun cross    A cross on a head-up display that is used for
    aiming M61A1 cannon rounds. 

HARM   High-speed Anti-Radiation Missile, used to 
    destroy radar installations.
heading   The direction in which the nose of the airplane
    points during  flight.  It is the course corrected for wind.
heat signature   An infrared "portrait" of an aircraft or
    other object which determines its vulnerability to
    heat-seeking missiles.