Aerophilately is the branch of philately that specializes in the study of airmail (stamps or covers transported by air).

The first registered airmail service was conducted by balloons in the 19^th century in France during the siege of Paris (1870-1871) in order to circumvent North German Confederation forces besieging the city (Franco-Prussian War).

World’s first official airmail stamp was issued in Italy on May 16, 1917 (Scott C1) when Italian postal authorities overprinted an existing 25 centesimo Victor Emmanuel III express delivery stamp for use on experimental airmail flight between Rome and Turin (Torino).

The first U.S. airmail stamp produced for a regular service is the 24¢ carmine and blue “Curtiss Jenny biplane” stamp (Scott C3) issued on 15th May, 1918 when the first official airmail between Washington, Philadelphia and New York was inaugurated. It was printed in a distinguishing bi-colored format (red and blue) depicting Curtiss JN-4 airplane in the center. The reason for 24¢ denomination of the stamp was primarily due to the fact that on May 6, 1918 U.S. Post Office Department had authorized airplanes to carry mail at a rate of 24¢ per ounce. It is worth mentioning that the stamp was also valid for non-airmail postal use as the 24¢ rate included special delivery service fee of 10¢.

In Germany, during the 1920s and 1930s dirigibles were used extensively for the transport of mail that is better known as Zeppelin mail. Zeppelins have provided a fast way to send mail over large distances and were very popular at the time.

In the early 20th Century, airmail was a premium service which required paying special postal rates. Early airmail items are highly prized and sought after by collectors.

Introduction of air transport of mail had generated immediate interest among philatelic community at the time and airmail services have been extensively studied by philatelists ever since.

In the last century, continuous technical advancements enabled a rapid progress in the delivery of airmail. Considering the role and impact airmail services had on worldwide communications provides a wide range of choices for a collector to pursue according to his/her interests.

In certain instances, ordinary postage stamps were overprinted in order to be used for airmail. Often, overprint consists of textual inscription including word “AIRMAIL” and/or image of a plane. It should be noted that word “AIRMAIL” is presented with equivalent inscription “PAR AVION”, “POSTES AERIENNE” or “CORREO AREO” etc. depending on the language of origin. 

Examples of very rare and expensive stamps intended for airmail usage are “Levanevsky stamp with an overprint, 1935” a Moscow-San Francisco flight via North Pole, with inverted overprint and small letter “f” inscribed, issued in 1935, a  “Consular Poltinnik” stamp,1922 a rare 50 kopeck Russian consular tax stamp with an overprint “Air Mail 1200 German marks” or “5 rubles deep green Air Mail” stamp, “wide 5” variety, issued in 1923 that rank as some of the most expensive Russian stamps in existence.

A Canadian “London to London Flight” 25 cent stamp or “60 cent Air Mail Francesco de Pinedo overprint” stamp from 1927 are other examples of very rare and expensive stamps.

In aerophilately, a special attention should be paid to identification of overprints, varieties, errors and postal marks in regards to the destination of philatelic item.

Appropriate reference literature is of essential importance in order to properly identify philatelic item.