[pfdietz]

At global distances a fraction orbital trajectory would use less total rocket delta-V.

More practical would be a trajectory that was a series of small suborbital arcs with skipping off the atmosphere (perhaps with some airbreathing propulsion during the skips.) The thermal protection can cool by radiation between the skips.

[seabass-labrax]

That would be very cool to witness! SABRE sounds like it would be an ideal engine for that application.