http://wired.com/news/space/0,2697,67876,00.html
"A new spacecraft has been successfully dropped off a launch jet into a vertical, midair blastoff position, an important innovation that could simplify future space launches. [See photos]"
Okay, what about the Gs for the passengers/pilot?
This thing is freefalling. Even if the engine kicks in right away (not too fast, else they may hit the plane ^^;), I think it still gonna be a hell of a ride.
Accelerating to orbital velocity will always be a rough ride if you do it by thrust alone. Orbital velocity is some 7000-8000 km/s, so the little bit of extra velocity you get from the freefall is pretty much nothing.
Escape velocity never changes.
It's alawys escape velocity.
ride my rocket