I wouldn't use boosters even if it was a thing. You'd have to have somebody on the ground to retrieve them, they would fall on people heads and generally be a pain.
But a connector element. That would be pretty neat. It would be useful in ship transport, or to do things like sending a satellite in orbit or whatever, there would be a tons of nice applications, ship rescue, all that.
You'd need an option on your construct to allow/forbid towing, otherwise the griefing potential would be over the roof. And then it would be pretty good.