Well it is shaped likea whale, and is a huge space/air-ship hence the name whale.
It was a nifty final airship in an FF though. I say it beats VIII's pathetic attempt of a space-airship easily. I mean it's a frickin giant whale shaped space-airship that has a crystal in it that powers it to travel to the moon. Plus it has a fat chocobo onboard. I mean how can you beat that?