The revelations last week that airlines overbook as a policy and that they can forcibly remove passengers when their calculations go awry has shocked millions from Chicago to China. But it's a problem as old as the airline industry itself.

As they expanded service in the late 1940s, airlines struggled with the problem of "no-shows" — people who reserved a seat but failed to board. This was a serious problem: A half-empty plane — even one with a few empty seats — could operate at a loss, or with severely diminished profits.

Overbooking was the solution, albeit one likely discovered by accident. Prior to the 1950s, airline reservations were a low-tech affair. Each airline had a "master board" at headquarters that showed all the available seats on any given flight; regional offices maintained versions of the board as well.