I too agree that what we saw at Scott was a C-140 Jetstar.

That makes sense. A unit at the base used to operate the type and one
is evidently being preserved for display on the future
http://www.scottfieldairpark.org/

The fairly ubiquitous Air Force fire trainer (e.g., the photo someone
posted earlier at
http://www.932aw.afrc.af.mil/shared/...1348P-8110.jpg)
is, I gather, a generic representation of a jet, made out of fairly
thick steel, rather than an actual retired aircraft -- presumably it
gives greater safety for the firefighters and much longer use than a
real fuselage. (Various civilian airports and perhaps some military
units *do* use actual derelict aluminum-type aircraft in their
distant hinterlands for firefighter training, but with smoke
generators only, AFAIK.)

Such a fire training facility is usually installed in a shallow
circular concrete bowl for containment purposes. In the photo
note its proximity to a stand of trees and the water tower. I think
that's almost due north of the probable C-140, inside the corner of
Locust and Van Buren Streets.

--Joe