Comment by AngryData

Slow moving free floating objects are super easy to move around. You can push a 100 ton piece of equipment with your hands if it is floating. That is why cargo boats still beat out shipping efficiency of rail. There is almost no practical size or weight limits, your only real potential loss, and potential gain, is the movement of your floating fluid be it wind or water, which in the case of air is fairly predictable these days, on top of moving in different directions at different altitudes.