When GPS first came out a bunch of boats got their fronts
smashed in on buoys. You see, with DR navigation, you usually
miss your target. Even with Loran C, you just get within sighting
range.

With GPS, you get right there. In-built defense-related inaccuracy
aside, you usually get right there.

So guys would set the GPS for the sea-buoy, couple it to the
auto-pilot, and at the ETA sure enough, they'd arrive
at the buoy!

Aeronautical navigation is remarkably like terrestrial
navigation, in fact. Even under VFR (visual flight rules)
restricted airspace, etc., means we don't often fly 'as
the crow flies.'

It's more of a case of 'fly 063 degrees for 60 miles to
the first way-point' (which may be a geographic feature or
an aeronav construct), then 'come to 050 degrees for 8 miles'
then '045 degrees for 100 miles, look for the airport five
miles out.' When you hit the first waypoint, the GPS notices,
and tells you (or the autopilot) where to turn next. Of course,
you may have to change altitude, if for example, you change
from an easterly to westerly heading, to follow conventions.

The ones for cars are a bit nicer in many ways, because they
have the anticipatory stuff--- "In 1/4 mile, turn right" as
they have to on vehicles that are restricted to roads.