HISTORIC AIRPLANES: Unusual
While official airmail usually traveled aboard
airplanes, balloons, helicopters, autogiros and even missiles
have carried mail for the U.S. Postal Service. Some experiments
worked out better than others.
While the U.S. never developed regularly-scheduled lighter than air airmail service, German Zeppelins criss-crossed the globe, carrying U.S. mail to and from foreign ports. In the U.S., mail was occasionally flown by balloons and blimps. Many of these trips were promotional stunts. Military blimps such as the U.S.S. Akron sometimes carried mail, but their reliability was dimmed by disasters such as the fatal crash of the Akron in 1933 and the Hindenburg in 1937. Helicopters played a small but steady role in mail transportation in the mid 20th century.
It didn't always take wings or hot air
to get envelopes into U.S. airspace. The postal service, working
with the U.S. Navy, used a missile to carry mail from ship
to shore in 1959. Twenty-three years earlier, private citizens,
with the assistance of their local postmaster had fired mail-carrying
rockets from Texas into Mexico.