How come all planets travel on along the Plane of the Ecliptic?

Why do all of the planets travel across this celestial line? In the present model of the solar system, all of the planets travel around the sun at relatively the same angle. I don't really know how to phrase the question without some kind of diagram, but why is there not a significant angle?How come all planets travel on along the Plane of the Ecliptic?centrifugal force basically. all of the planets formed out of the same disk of gas and dust. that disk was spinning so centrifugal force flattened it out into a disk.How come all planets travel on along the Plane of the Ecliptic?--Vestiges of the original accretion disk.

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