If you're going fast enough, you don't need lift.

But judging by "in four hours" I'm guessing he's imagining something somewhere in between those two extremes. High enough to substantially reduce drag, low enough that you don't need to approach orbital velocity to maintain altitude.

"Fast enough" is very nearly orbital speed, though. Suborbital range is very short on the lower end, and increases rapidly and nonlinearly later. E.g. if you can boost to 2km/s (~ Mach 7), this gives you, I kid you not, around 200km of ballistic range. It's either atmospheric flight or orbital flight, and there's nothing really useful in between.

GP is not talking about a ballistic trajectory though.

One possibility is a trajectory that's a series of skips.

There actually is still significant lift. We define the edge of the atmosphere to be where the lift to drag ratio of a plane would be less than 1 below orbital velocity (ie if you were going fast enough to lift your weight with conventional wings you'd be in orbit), so you can't fly conventionally in space but lift might still be generating a force which is significant compared to your craft's weight.

Well the assumption was that there is no drag because the air density is so low. You can’t just say there’s no drag but still assume that you get lift. Your lift/drag ratio won’t go up infinitely just because you’re flying higher.

GP's assumption was travelling through space to avoid drag which doesn't necessarily imply generating lift in space.

My comment was not a support of that argument, but a clarification that simply being in space does not automatically mean no aerodynamic forces. I'm also not saying L/D increases, actually the opposite happens at higher speeds and altitudes.