Dick Heckman writes:

Below you'll find the FAA rule that we're operating under and that
presently will continue as is in the rules to go into effect in 2020. This is an
aircraft rule and we are air vehicles but we're assuming that if they can fly,
so can we. The FAA could easily change it at any time if we abuse it. When we
see something like this, we need to realize just how much flying access we have
here in the US. Think if every state had jurisdiction over their own airspace
(like in Europe):

Mode C exception for non electrical system aircraft

FAR 91.215(B)(3)

(3) Notwithstanding paragraph (b)(2) of this section, any aircraft which was not
originally certificated with an engine-driven electrical system or which has not
subsequently been certified with such a system installed, balloon or glider may
conduct operations in the airspace within 30 nautical miles of an airport listed
in appendix D, section 1 of this part provided such operations are conducted-