a lot of misinformation here backed up by sites that have misinformation. Basic physic classes sometimes use the electron flow model as a simple way to explain things, but they are simply wrong.
The AC signal that is transferring energy from the source to the load (amp to speaker for example) is NOT doing so by moving electrons from the source to the load. Electrons are NOT flowing down the wire like water through a hose.
Think about it..
The energy will flow through a capacitor which has an insulator in the middle of it. How do the electrons flow through an insulator?
The energy can travel through a vacuum where there are no electrons, think radio waves.
High frequency AC waves are commonly sent down tubes called waveguides which are hollow = no conductor = no electrons.