How is the movement of electricity in air different than the movement through copper?

Answer 1

It's first important to realize that what one might call the movement of electricity is actually the movement of electrons between ions, which then creates the electric current. Electrons are the thing that's moving, not the electricity. This explains why electric current flows so much more easily through copper than through air. Copper atoms give and take electrons more easily than most of the particles in air. The atoms in solid copper are also way closer to each other than the particles in gaseous air, leading to a more efficient flow of electrons through copper. Air is actually considered to be an insulator of electricity because the combination of long distances for electrons to travel and the stable nature of air particles make it relatively difficult to pass a current through.

Copper is usually drawn into wires, so the current moves in a very predictable direction that follows the wire from negative to positive in the shortest path. Electrons will still bridge the gap between negative and positive through air, but it's not quite as consistent partially due to the way air is so dynamic and isn't the same everywhere.