This is not accurate. Cell towers don't see very high (6,000-10,000 feet anecdotally in GA aircraft) because of the radiation pattern used by the tower antennas - think of a donut laying on it's side and you'd be close to what it looks like. There are other considerations as well that make cell service in an airplane problematic, but none of them involve cell towers being programmed to "ignore airborne targets".

This is a good summary for the layman - I can dig up a much more technical explanation if you need it. link