No encryption whatsoever. The systems are primitive analog systems, about the le...

No encryption whatsoever. The systems are primitive analog systems, about the level of WW2 guidance technology. This is also not news to anyone who bothered to read Wikipedia or Stackexchange.

https://en.wikipedia.org/wiki/Instrument_landing_system and https://aviation.stackexchange.com/a/2661, compare https://en.wikipedia.org/wiki/Battle_of_the_Beams