5c Buffalo Balloon imperforate vertical pair

1877

Perhaps the most enigmatic of all American stamps, the Buffalo balloon stamp is certainly among the premier rarities in aerophilately. This stamp begs the question, “What is an airmail stamp?” Described variously as “experimental,” “semi-official,” “a carrying label,” and even as a vignette or cinderella, the fact remains that it was the first of its kind ever issued. Since it was privately issued for use with a standard U.S. postal service 3-cent stamp to pay for air handling of a mailed piece, it was (if one includes both private and government issues) the world’s first airmail stamp.