So there's a couple interesting things here. In airport areas, it's pretty common for that type of separation during takeoffs and landings, but you're under 25

So there's a couple interesting things here. In airport areas, it's pretty common for that type of separation during takeoffs and landings, but you're under 250 knots airspeed. This case is different. At FL300, you're flying at cruising speeds, and usually on airways. Hence the .2 nm lateral separation. In a GPS world, you're flying the exact centerline of the airway and will have no lateral separation with other aircraft on that airway unless you "fly right." An example of an accident because of that is the one in Brazil, where a private jet's winglet sliced through the wing of GOL 1907, a 737. https://en.wikipedia.org/wiki/Gol_Transportes_A%C3%A9reos_Flight_1907 https://en.wikipedia.org/wiki/Gol_Transportes_A%C3%A9reos_Fl... So this was a pretty big deal. Source: commercially-rated airplane pilot.