Cortex's airship

Cortex's airship is an airship used as transport for Cortex when he's not using his hoverboard. He always hangs the airship from a rope tied to his current base.

Crash Bandicoot
The airship is first seen tied to Cortex's Castle in the intro in the outside view of the castle. Later, in the level select map, it is portrayed as the warping area for Cortex's boss fight. During the boss fight, Crash stands atop the airship to fight Cortex, and when he is defeated, Crash and Tawna ride away on it. Also, in the alternate ending when Crash and Tawna escape on a bird, it can be seen again tied to the castle. In the boss fight with Cortex Crash can also jump off the airship, causing him to lose a life.

Crash Bandicoot 2: Cortex Strikes Back
The airship can be briefly seen as Cortex falls in the intro, but has a metal balloon instead of a purple helium-filled one.

Crash Twinsanity
The airship plays a much larger role in the game. When the Psychetron maulfunctions and Cortex suggests to go get Nina to fix it, he points towards his airship for transportation, and they take off in it. Inside, they are ambushed by the Evil Twins and their Ants. Upon defeating them, they progress towards the Academy of Evil. After Crash travels through the school and meets up with Cortex, Cortex orders Crash to tie the Airship rope to somewhere secure, but he mistakes the order and attaches it to a school bus which it floats off carrying it. Later, Nina is chased by it and manages to secure it. It can always be seen in the Academy of Evil and the Iceberg Lab attached to it by a rope.

Crash of the Titans
Cortex arrives in his airship in the intro with an entirely different model, and he captures Coco and Aku Aku with cages and freezes Crunch with a freeze ray from a cannon. He carries off with Aku Aku and Coco, but Crash throws Coco's butter recycling device at Aku Aku's chain that is connected to his cage, thus severing the chain and freeing him. Later, Cortex uses a Mojo pumping device from the airship to steal the Mojo from the Mojo Temple.

Crash: Mind Over Mutant
The airship appears in one of the unlockable concepts where it is seen in one of the fan-made drawings in the picture of the islands, where its old variant can be seen attached to an unknown Island.

Crash: Mind Over Mutant (Nintendo DS)
One of the mini-games involves Crash running down a path kicking balls at Cortex's airship for points.

Trivia

 * For some reason, in the intro of Crash 2, Cortex's blimp balloon turns from a helium-filled balloon into a metal balloon.