If we're working on the laws of physics, things like that win. But in space launch, the laws of engineering have tended to be more important. A very reliable r

If we're working on the laws of physics, things like that win. But in space launch, the laws of engineering have tended to be more important. A very reliable reusable rocket is probably going to be a better investment of the marginal dollar than any kind of air launch. (Unless you are going all the way to things like Stratolaunch, which is riding SpaceX's rocket reliability. The mothership ought to be quite reusable, but building the biggest wing ever in history is going to be a tall engineering order. It remains to be seen which way wins out in the end.)