mstram, to answer your original question e no airport restrictions, I suppose the limit is imposed by the materials we use. In theorey an aircraft could be built as big as you wanted as long as the metals and composites used can cope, but I doubt that would be a problem, after all we build ships up to a million tons in steel.
There will be a practical limit with number of engines I suppose, but if all is automated
I gusee that is less important.
Thare is a huge solar powered flying wing being developed in USA with huge span and lots of little electric motors all along the wing.
If there was the will, funding and need why not a mile span with dozen Tays along it's length??? I bet it could be done.
Ask Bert Rutan, he'll design it for you!