When speaking about errors, collectors must keep in mind the difference between errors of execution, which are rare, and errors of design, which are not. Sometimes a designer improperly researches his subject and a person is shown in a setting that is historically incorrect. Such historical anacronisms abound on stamps, as do wrong names for places and pictures. But unless the stamp-issuing authority ceases production once the issue is discovered, and corrects it, the error of design in and of itself does not cause the stamp to be rare.
The Airmail invert is an error of execution, not of design. Its price, as America’s most popular stamp, has been meteoric. By 1939, a copy had realized $4,100. During the war years, the stamp market was relatively quiescent as the country had more on its mind than hobbies, no matter how fascinating. By 1969, the stamp was selling in the $30,000 range. Five years later saw it in the high $40,000s. In 1978, the first copy sold for $100,000, and in 1980, a block of four that had sold four years before at $170,000 was traded for half a million dollars. Prices of Airmail inverts, like all stamps, are dependent on the quality of the specimen. Defective or straight-edged copies bring about half the price of perfect ones.
Paying the price of a nice house for a tiny piece of paper strikes many people as odd. In 1918, when Green bought the entire sheet of 100 for $20,000, the New York Times stated editorially what most noncollectors have thought more than once: “At this time there are several better uses for $20,000 than the purchase of a set of stamps which, except for a printer’s error, would be worth just $24 in the open market.” Still, there is something exciting about owning something of which fewer than sixty can be bought (there are the “lost” inverts, and about twenty-five in institutions). And the Airmail invert, expensive as it is, cannot even lay claim to being the most expensive stamp in the world. That honor belongs to our next specimen.