Jupiter

I like Poul Anderson's descriptions of vast three dimensional environments traversed by space explorers. see here and here. Another is the Jovian atmosphere. I know three kinds of fictional Jupiter:

those with a solid surface;
those that are dense gasses all the way down to a solid core - real gas giants;
the one in Poul Anderson's "What'll You Give?" which has a surface although it is too far down under a dense atmosphere for anyone to see it.

In that third case, Anderson describes a flight through the atmosphere. We will consider this in more detail when I am not rushing out to a social event.