GPS Facts

The caller mentioned on the air having posted his opinions on tt-watch, quoted here. He also mentioned on the air having worked for the FAA, but here states he works with them while maintaining planes:

Actually, I worked with the FAA not for them. However, I've been involved in aviation
since 1976 and wrote pilot training manuals for eleven years. I now write maintenance 
publications for a large aircraft modification center. 

Her post about GPS is still so full of holes it's pathetic. 

The first civilian GPS products did not appear until the mid 1980's and GPS products 
for the general aviation community did not start appearing until the early 1990's.

Certified for non-precision approach units did not appear until the mid 1990's. 

GPS and civilian aviation have a very short history in relative terms. 

Before that there was radio range (obsolete), VHF-Nav (almost every GA aircraft has one 
or more), ADF (pre-dates VORs), Inertial Navigation System (INS - only the big boys and 
the military have these).

Enough of my rant.
Tom

In his own words, he states that

1. GPS for planes was developed,
2. certified,
3. in use but with a short history.

GPS has been employed as compasses have been failing, thus, only recently. Because the compasses have been failing, GPS has in fact been pushed as a replacement for compasses for small planes and their landing strips.

Smaller Airports To Get GPS-Like Guidance Systems Early
Source: Newsbytes

By Don Phillips, Washington Post WASHINGTON, D.C., U.S.A., 13 Mar 2002, 7:49 AM CST 
Regional airlines, business aircraft and small private planes will be able to land 
more safely at more than 2,500 small airports using satellites for guidance under 
new procedures to be introduced by the Federal Aviation Administration starting late 
next year, two years earlier than planned.

Recent discussion on how terrorists might use GPS and shutting the system down during a terrorist attack, clearly states it is used in airplanes.

Global Positioning System
Dec. 15, 2004
Source: MSNBC

The GPS system is vital to commercial aviation and marine shipping. The U.S. network comprises more than two dozen satellites that act as beacons, sending location-specific radio signals that are recognized by devices popular with motorists, hikers, pilots and sailors.

The Gulfstream to carry Bush Sr. to Ecuador was noted to have a GPS system on board. Discussion among pilots, including those who fly into and know the Love airport.

Most Gulfstreams as top of the line jets would have redundancy with IFR GPS back up systems

Surely the have a GPS working in conjunction with the nav, even that would show 3.4 miles to threshold.