JB wrote:
Hence photons travel best without ether.

Photons cannot travel at all without ether because
the absence of ether means there is nothing through
which to travel. Photons simply cannot travel outside
of the universe into absolute nothingness.

How does ether affect the velocity factor of light?

The velocity factor of free space ether is 1.0.
The velocity factor of absolute nothing is zero.
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein