Airmail was enormously important in the US because of the country's size. Photo no. 2 shows mail being loaded on to an aircraft in Cleveland. In other parts of the world, airmail quickly became international. The first scheduled international service flew from Folkestone, in the UK, to Cologne, Germany, delivering mail to troops. Throughout the 1920s, the British Royal Air Force expanded airmail routes to the Middle East.
In 1918, Latécoère Airlines, later renamed Aéropostale, began France's first international airmail service connecting Toulouse and Madrid, Spain. Later, the company expanded as far as Dakar, Senegal, where mail was loaded on to ships for South America. The image on the right is a 1929 poster advertising the service.
Since aircraft couldn't cross large oceans, Luft Hansa - the forerunner of Germany's Lufthansa - created an innovative ship-to-shore service in 1929. A Heinkel seaplane (picture no. 4) was catapulted off a ship and flew up to 900 miles - significantly reducing the time mail took to reach the US by 20 hours on westward trips and as much as two days going east.
The "flying boat", which depended on the fuselage for buoyancy, like the hull of a ship, allowed aircraft to refuel at places with no airfield. The Latécoère 300 (picture no. 5) was an Aéropostale seaplane - and the first powered by a Saft battery to start the engines. First flown in 1931, in 1933 the 300 set a record for the longest non-stop flight by a seaplane, on a trip from Marseille to Saint-Louis, Senegal. The aircraft later transported mail across the Atlantic, between Senegal and Brazil.
The reason that airmail was so important to early aviation is that most aircraft could not carry enough people to make a passenger service economical. Instead, aircraft development was driven between the wars by colonial powers, such as France and Germany, who needed airmail to communicate with their colonies. By 1931, it was possible to send a letter from Britain to Australia in 16 days, compared with a month by sea. In the photo opposite, British Postmaster General, Sir Kingsley Wood, watches airmail for Egypt and the Sudan being loaded on to an aircraft at London's Croydon airport in 1932.
By 1930, when the poster on the right was designed, Aéropostale was operating regular routes to Africa and South America, as well as across Europe. However, the company was dissolved in 1932 after a scandal over the misuse of postal payments from the French government.
In the 1930s, flying boats became large enough to carry passengers as well as post, creating an era of glamorous travel. The Short Empire (picture no. 6, above) was developed for Britain's Imperial Airways and could carry 17 passengers. It could even be refueled in the air, making it possible to cross the Atlantic without landing.
In 1938, Boeing developed the 314 Clipper for Pan Am. One of the largest aircraft of its day, it had 74 seats that could convert into 40 bunk beds. Designed for luxury travel, passengers would enjoy six-course meals on board and there were dressing-rooms for male and female flyers. Pictured below, no. 8, is the Yankee Clipper being loaded with mail. That aircraft was destroyed in 1943 when it crashed while attempting to land in Lisbon, Portugal.
After the Second World War, seaplanes were replaced by land-based aircraft that could carry more passengers and fly long distances without refueling. Airmail became just a standard part of airplane cargo. Photo no. 7, taken in 1953, shows an Air France McDonnell Douglas DC3 being loaded with mail.
For a brief period in the 1990s, the Aéropostale name once again appeared on aircraft as part of a joint venture between Air France and La Poste (photo no. 9). That venture ceased in 2001. If it wasn't for airmail, international flight would have developed far more slowly. Today, airmail is no longer anything special. Even "standard" mail will often be transported at least in part by air. Eighty per cent of modern commercial airliners rely on Saft batteries and Saft also plays a role in the email and telephone communications that have taken away much of the demand for airmail - powering many of the satellites that share data.