Basically they'll stick a recalcitrant inmate on the regularly scheduled prison transports between prisons for whatever reason.
They're handcuffed, probably shackled, and they go for a pretty miserable ride. Adding to the discomfort, they get very "binding" sandwiches. Sort of the same effect as two weeks on bread and water.
Just try going to the toilet when you’re shackled the way they are, especially on a Con Air flight. Really sucks. Just read “Orange is the New Black”.