Air and earth think differently: one lives on ideas and motion, the other on results and consistency. With respect, they complete each other — one's ideas land thanks to the other. Without it, one feels tied down and the other dizzy. Translation is the key.
One launches (cardinal), the other adapts (mutable): natural flexibility — few head-on collisions. Just don't let direction always come from the same person; the mutable one needs to be heard too.