Orbital Sciences is doing something similar, IIRC. They are the two big approaches to cheap space being done now. 1) Be cost-effective at making rockets, 2) l

Orbital Sciences is doing something similar, IIRC. They are the two big approaches to cheap space being done now. 1) Be cost-effective at making rockets, 2) launch from jets. My money is on #1, which SpaceX is doing, but #2 has some things going for it that could prove me wrong. #2 is also strictly limited in just how big you can make a payload, while for #1 you can get up to around 200 ton payloads before things start working against you.