Maybe Oumuamua was a carrier and something got off. It would make sense. It could also have been a spent deceleration stage. All speculation of course, since we

Maybe Oumuamua was a carrier and something got off. It would make sense. It could also have been a spent deceleration stage. All speculation of course, since we just didn't get a good look. Of course if whatever got off wants to ever go home it would need to set up shop somewhere and build a new multistage interstellar rocket. You could probably do that in the outer solar system and not be noticed. People who dismiss UFO sightings have among other points argued that the small craft sighted are too small to have the kind of crazy propulsion systems required for interstellar flight. That makes sense, but why assume those are interstellar? A staged fusion rocket or something would make more sense. The small craft would be interplanetary scale.