If a plane goes v mph wouldn't it go v +0.285831 mph because of the earths speed rotating per second?
The first thing you should understand is that the Earth's surface does not rotate at a constant speed. The linear speed of the ground about the axis depends on your latitude. It is fastest at the equator and goes to zero at the poles.
The next, more important point is relativity (Galilean Relativity). When dealing with speeds/velocities it is important to understand that there is no such thing as an absolute speed. Velocity can only be meaningfully expressed with respect to some reference frame. Relative to the Earth's surface, the plane moves at the same speed regardless of the rotation of the Earth. The atmosphere itself is spinning along with the Earth and a plane will not get any sort of noticeable ground speed boost or decrease as a result of flying East or West respectively. However, relative to some reference frame beyond the Earth, then yes, as seen from space the plane will move with the greater velocity thanks to the Earth's rotation. In fact, high speed jets often make a point out of flying against the Earth's rotation (West) at sunrise or sunset at precisely the same speed as the ground but in the opposite direction. Causing the effect that the sun seems to hover at the same height in the sky.