Mark Evanier points us to another great commercial, this one with Donald Duck and Porky Pig. As he points out, they don’t appear together and that was probably a condition of being able to use both of them in the same commercial.
What I thought was interesting is that Disney let Warner Brothers’ Porky have the last word, get more screen time, and sing the song at the end. My understanding was that for Disney and Warner Brothers characters to appear together in Roger Rabbit, they had to have equal screen time with whoever they were appearing with: i.e., Bugs and Mickey in the skydiving bit. Maybe it was adverts like this that let them figure that out.
Direct link for the feedreaders.