Imagine how many of these could fit on a single flat road. Then imagine stacking dozens of roads on top of that. Then imagine the roads are several times wider because there isn't any property or buildings in the way up there (with the exception of a few tall buildings in big cities.)

It will be a long, long, long time before we run out of airspace. It isn't the limiting resource at all.

I never doubted that we dont have enough of airspace, my question was can these lightweight machines make proper use of all that open space? how high can they fly? Because i am assuming these are relatively low-altitude aircrafts.