From the Military side of things...
Chinook - Chook (nickname for a chicken in Australia for our O/S mates)
Black Hawk - Schnorker (only used by non Black Hawk pers)
Kiowa - Kenny
Twin Otter - Twatter
F111 - Pig (derives from the official name for an F111, Aardvark which is Dutch for 'earth pig'.
Nomad - Gonad
From the GA side of things...
Bandierante - Bandit
Piper Cherokee - Pooper Chickapee
Duchess - Gutless
Keep 'em coming ladies and gents.