It's worse than you know. Ancient computer systems, non-ASCII character encodings, analog phone lines, and ticker-tape weather. You'll also be surprised to lea

It's worse than you know. Ancient computer systems, non-ASCII character encodings, analog phone lines, and ticker-tape weather. You'll also be surprised to learn there's still parts of the US where there's no radar or radio coverage with ATC, if flying at lower altitudes. (Heck, there's still a part of the Pacific Ocean that doesn't have ATC service at any altitude.) Aviation drove a lot of the early developments in networked computing, which also means there's some really old tech in the stack. The globally decentralized nature of it all and it being a life-critical system means it's expensive and complicated to upgrade. (And to be clear, it does get upgraded - but it in a backwards compatible way.) Today's ATC systems need to work with planes built in the 1950s, and talk to ATC units in small countries that still use ancient teletype systems and fax machines. But yet it's all still incredibly safe, because the technology is there to augment human processes - not replace them. Even if all the technology fails, everything can still be done manually using pen and paper.