Air Post: The carriage of mail by air. The first regular airmail service began in 1870, when mail was carried from Paris, France, then besieged by German forces, over enemy lines by balloon. The first airmail stamp was issued by Italy in 1917.
Air mail in the U.S. postal system developed in three stages: pioneer period (with many unofficial or semi-official flights before 1918), government flights and contract air mail (C.A.M.). Contract air mail began on February 15, 1926. All C.A.M. contracts were canceled in February, 1934, and air mail was carried by Army planes for six months. After that the contract plan was resumed. Separate domestic airmail service was abolished in 1975.