Prospective Member...with questions (go figure!)

[Hawk200]

I have always understood the problem to be that you would hit too many towers from altitude and cause problems for users on the ground.

That used to be a problem with some of the older analog cell networks, but it's not really a problem now. Digital cell service is pretty quick, and once a particular cell site is selected by your device, the other sites will ignore it except for handoff. Your cellphone itself actually chooses which site it connects to, and selects the strongest signal that it can receive from, and more importantly connect to. The less power your phone needs to use to connect, the longer your battery life.

Watch the battery on your phone the next time you have a low signal, you'll find that the battery drops a lot faster when the signal strenth is low.

I do remember cellular systems that installed in aircraft, completely in the avionics panel, and have antennas that mounted on the belly. Haven't seen any lately, they may still be around. Don't really know at present, not like I have my own aircraft to install one in  .