Living in a town where real satellites are build ..
I happen to know some people who are in R&D as well as in production. And from them I know that they hope for a runway launch like SpaceShipOne but bigger.
Especially the smaller satellites for lower orbits are heavier then needed for their purpose to survive the first 30 seconds until after the second stage ignites. Eliminating the first stage and launching the second one from a plane would help building much cheaper satellites.