A hand plane is for both thicknessing and straightening a board. A hand plane does not remove the same amount of material unless the board is already flat. The long flat heel of the plane serves as a reference surface. There is some skill required to not taper the workpiece and you can use winding sticks to check your progress as you flatten the workpiece.
A router sled/CNC router will be able to accomplish the same thing.
A hand plane is for both thicknessing and straightening a board. A hand plane does not remove the same amount of material unless the board is already flat. The long flat heel of the plane serves as a reference surface. There is some skill required to not taper the workpiece and you can use winding sticks to check your progress as you flatten the workpiece.
A router sled/CNC router will be able to accomplish the same thing.