Maybe start with the original White Knight and Spaceship One?
Someone already did it, it was in the FliteFest 2016. It's on this
video, at minute 24:30. It didn't work, though, but it worked this other
video (they used the rocket at 4:00).
But you might need a second pilot if you don't want to crash one of the 2 planes, or maybe making the Spaceship just a non-RC glider with a rocket, and a parachute in case you want to recover it (similar to the model rockets system).