Eh. e.g. the north atlantic tracks have been around since the 1960s. GPS wasn't available to the public until Korean Air Lines Flight 007 in the 1980s.
The OP means that satnav ensures that two aircraft on a reciprocal or identical track will now pass over one another, whereas there used to be navigational slop that would give some unintentional but useful lateral displacement.
Ironic that you should use the term 'slop', since that's exactly how they avoid flying the same route across the Atlantic tracks for example (Strategic Lateral Offset Procedure).
dingaling|9 years ago
cjrp|9 years ago
dmix|9 years ago
Woah, the soviets shot down a Korean airliner with air-to-air missles killing 269 people? Never heard that story. Crazy.
https://www.wikiwand.com/en/Korean_Air_Lines_Flight_007
macintux|9 years ago