The name was changed due to expanding to more than plane models, but it's from the same creator- it's sort of a continuation. If you've purchased Balsa Flight Sim, you'll have access to Kitbash (at least according to a news post from March).
It's actually a LOT bigger in scope than balsa was, the map alone is HUGE compared to the old balsa one, and has a ton more gadgets and parts for boats and cars
