Here's the link for the above post, along with some more pertinent info.
http://www.globalsecurity.org/military/facility/smyrna.htm
Located twelve nautical miles south of Nashville Airport, Smyrna Airport is the "reliever" airport for Nashville. With over 1,700 acres, Smyrna Airport is the third largest airport in Tennessee and the busiest general aviation airport in Tennessee. Smyrna Airport users have, within ten miles, access to rail and three interstate systems which transverse Middle Tennessee. Smyrna Airport is located in the geographic center of Tennessee and more importantly the center of the eastern United States. Eighty percent of the United States population lives within a 700 mile radius of Smyrna. These factors influence the location of industry in the Smyrna area.
Well now that is an eye-opener.
That's interesting.
Now, *that* is an interesting factoid.