Raeford, those routes are pre-approved tracks along the ground for military planes to do low-altitude practice bombing or reconnaissance missions. They are published on aeronautic charts so other pilots (in bug smashers) can avoid them. Not that they all do. There's a low-level route that ends at a canyon mouth only a mile from my house. In addition to the F-16s and now F-35s that scream out of that pass regularly, lots of Cessna and helicopter drivers fly down that canyon, too.
When Pugs says he flew them at 500 feet and 500 knots, that's 500 nautical miles per hour, or 575 of the statute miles per hour you're used to. In other words, he was down in the grass, haulin' ass.
