wiki.travellerrpg.com comfirms that "most air/rafts are capable of achieving orbit (occupants must wear vacc suits) but the trip will take several (6 - 8) hours."

IIRC, the CT wording was roughly similar, except that the time required was a number of hours equal to the world's Size digit.

Not sure how they get that flight duration, by the way. A standard air/raft's top speed is ~62 mph. Even assuming that it's only going as far as Low Earth Orbit, that it can rise vertically the whole way and that it doesn't need to accelerate to orbital speed (since it "weighs" nothing at all), that's still a trip duration of ~19 hours from sea level on Earth.