90's cartoon question...do you remember?

There was this cartoon that I vaguely remember. There was a female hippo character and a male worm. I don't think they were main characters, but they're the only ones I can remember. lol There was an airplane in the opening sequence that was pulling a banner with the title of the show, I think. They were always going on adventures and in one episode, they're afraid to go inside of a cave.

Ringing any bells for anyone? Because it's killing me...