Scattered among history's bright ideas are technologies that were doable yet not worth doing -- like on-the-fly fill-ups for automobiles. In a 1923 cover story, we reported that a new supply car had enabled another auto to drive 3,155 miles in 50 hours at the Indianapolis Speedway without stopping to refuel (though it still had to pull over for tire changes). Why bother? Automotive and aviation developers alike were obsessed with setting endurance records, in part because at the time, places to refuel were few and far between. The same article described a breakthrough in which four army aviators transferred fuel from one deHavilland DH-4 to another while "rushing through the air at a speed of 90 miles an hour." Early systems were tricky, with tanker planes sometimes unable to haul the hose back in; in one test, a pilot was forced to land with a 48-foot hose "dangling under his machine." On-the-road refueling never caught on, but the inflight version became a staple of military strategy.