With aviation developments, several countries started to experiment with flights, and postal authorities considered flying the mails. Initially flights were unofficial, but some flights such as the 1877 Buffalo balloon flight, carried mail, to which stamp-like labels were affixed. At the beginning airmail letters cost more than surface mail.
Both airmail stamps and stamps surcharged for airmail were issued, though some countries restricted the use of airmail stamps only to letters sent by airmail, while others allowed them to be used for other mail services.
Several of the early airmail stamps were produced by surcharging other stamps with overprints; at first in 1917, Italy used express stamps; regular stamps were used by Austria in 1918, Sweden used official stamps in 1920. Some other examples are the use of fiscal stamps, telegraph stamps, postage due stamps, and parcel stamps by other countries. Airmail stamps have been issued for extra services, such as registered airmail, express airmail, airmail fieldpost, and even with welfare surcharges.
 A new branch of collecting
In the 1920s and 1930s, when many countries issued airmail stamps to publicise their new airmail routes, a new branch of stamp collecting started. This led to an expansion that includes the collection of covers, and other postal items carried by aircraft. Airmail items from the early days are expensive due to the popularity of this collecting area. Specialised catalogues and albums are produced for collectors of airmail stamps and other aerophilatelic items. Many airmail stamps feature aviation themes that are an area of topical stamp collecting.
 Types of airmail stamp
 Official airmail stamps
The first official postage stamp to be issued for an airmail flight was in May 1917 when Poste italiane overprinted their existing special delivery stamps. The following year, the United States Post Office Department issued the first airmail stamp specifically issued for the purpose; while it does not have "airmail" or "air post" printed on it, it illustrates a Curtiss JN-4 airplane. One pane of 100 stamps were found to have an invert error, known as the Inverted Jenny, because the airplane image in the centre is inverted relative to the outer frame. The error is one of the most well known airmail stamps.
 Semi-official airmail stamps
Semi-official airmail stamps are not issued by the postal authority but have official sanction and are sometimes used for local posts, they are more accurately referred to a labels rather than stamps. The privately produced 5¢ Buffalo balloon stamps were used on June 18, 1877, for a balloon flight from Nashville to Gallatin, Tennessee.
 See also
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 References and sources
- Miller, Rick. "Have airmail stamps fallen victim to success?". Linn's Stamp News. Retrieved 2009-05-02.
- Lynch, Maureen & Chris (2006-05-18). "Arago: Air Post Semi-Official Issues". National Postal Museum. Retrieved 2009-05-02.
- Hornung (1970), pps. 94–95
- Williams, Leon Norman (1990). Fundamentals of philately, Rev ed. State College, PA: American Philatelic Society. p. 15. ISBN 0-933580-13-4.
- Hornung (1970), pp. 258
- Hornung (1970), pp. 262
- Solarz, Sanford (2008-09-18). "Scanning the Horizons:Collecting Aircraft on Stamps". American Air Mail Society. Retrieved 2009-06-04.
- Baadke, Michael. "Airmail collecting can take you anywhere". Linn's Stamp News. Retrieved 2009-05-02.
- "Fad to Fundamental: Airmail in America: U.S. Airmail Stamps". National Postal Museum. Archived from the original on 26 April 2009. Retrieved 2009-05-02.
- "Fad to Fundamental: Airmail in America: Inverted Jenny". National Postal Museum. Retrieved 2009-05-02.
- "Arago Glossary". National Postal Museum. Archived from the original on 30 April 2009. Retrieved 2009-05-02.
- Miller, Rick. "Another world: semiofficial airmail stamps". Linn's Stamp News. Retrieved 2009-05-02.
- Horning, Otto (1970). The Illustrated Encyclopedia of Stamp Collecting. Feltham, English: The Hamlyn Publishing Group. ISBN 0-600-01797-4.
- Schoendorf, Robert (1979). The Buffalo Balloon Mail 1873-1877. New York: Cosmos Press.
- Further reading
- Gomez, James; Ariel Books Staff (1996). U.S. Airmail Stamps. Andrews McMeel Publishing. ISBN 0-8362-0989-3.
- Newall, Alexander S. (1990). Airmail Stamps: Fakes & Forgeries. Newall Consultants. ISBN 0-904804-96-8.
- Vachon, Georgette (1974). Goggles, helmets, and airmail stamps. Irwin: Clark. ISBN 0-7720-0619-9.
- Buffalo balloon stamp on cover
- Collecting airmail stamps American Air Mail Society
- U.S. Air Mail Stamps American Air Mail Society