The red airship is Leofard's personal airship, which has a bit of a story behind it (and isn't really obtainable anymore, for obvious reasons, if you've finished the Mhach story).

The black one seems to be the standard Redbill airship though, and there probably wouldn't be much in the way of adding it. I'd like that one, at least, since it doesn't have that huge sail that's on the mana cutter.