On 2003-12-06 12:32:51 -0800, Jeffrey Voight said:

I would have thought that most
flights at altitudes that produce contrails would be on GPS plans....

Two things:

1. There are lots of big airplanes flying around that still have nothing more than
the good old VOR & DME.

2. GPS doesn't always mean direct.

--
Larry Fransson
Seattle, WA