I ordered something 2nd day air from a company that ships from Las Vegas. They shipped it last night, so it should be here tomorrow. I'm having fun tracking it on the net, watching what airplanes it gets on and so forth. And I'm learning something about why it's called 2nd day air. I had assumed that it got a lower priority, or made short hauls in trucks, or did some other thing that actually made it less expensive to ship. But no, it's 2nd day because it takes a much more convoluted route; the first flight it got on was in exactly the wrong direction, and its itinerary already has more steps in it to get to Los Angeles than I thought it'd need to get to Boston.
I have to wonder what capacity-planning program is able to come up with enough of these serpentine routes (on, presumably, otherwise unfilled aircraft) to make a viable business out of 2nd day air shipping.