well -an empty balloon may weigh a gram -but it can be filled with light gas to almost zero weight on any scale under conventional weighing conditions.
Not that tht matters
My point was that as we approach zero wingloading-the HARD rules soften/change -and when extremely light -the aircraft is far less critical to cg -
you can calculate till hell freezes over but in actual practice the airplane is still flyable as it moves along.
It is not a Piper Cub -or a hands off glider but it is still an airplane
maybe not one you would like .But still a powered , heavier than air machine.