All planets in our solar system orbit the Sun in roughly the same plane, called the ecliptic plane. So, to answer your question directly, no planet is *not* in the orbital plane.

However, the planets do have slight inclinations, meaning their orbits are tilted slightly compared to the ecliptic plane. Here are some examples:

* Mercury: 7 degrees

* Venus: 3.4 degrees

* Earth: 0.005 degrees

* Mars: 1.85 degrees

It's important to note that the orbital plane is not a perfect flat surface. The Sun's gravity pulls on the planets, causing them to wobble slightly and their orbits to change over long periods.

Therefore, while all planets are in the general vicinity of the ecliptic plane, their orbits are not perfectly aligned.