First airmail flight in the world - British India

Humber-Sommer biplane. First airmail service. British India. between Allahabad and
Allahabad cover flown on the world's first aerial post in 1911/
With the advent of internet and E-mail privileges, though the air mail services have come down drastically in the last decade,  still we have to depend on airmail services to send certain items abroad. It is easy, convenient and much faster than surface transport or through ships.
Airmail (or air mail) is a mail transport service  that involves sending letters, packages, etc through the aircraft.  Airmail items reach the destination faster, but the cost is much more than other services. The advantage is airmail services are commonly used to reach the overseas destinations across the globe.  In 1929 at Postal Union Congress in London, the Universal Postal Union adopted comprehensive rules for the airmail. As the official language of the Universal Postal Union is French, all airmail items worldwide are often marked Par avian , literally: "by airplane".
First airmail service. British India. between Allahabad and Naini.
In the early days centuries ago transmitting of message was a difficult one.  Man trained the homing  pigeons  and had used them  to send messages (an activity known as pigeon mail) over long distances. During the war time between kingdoms, homing pigeons were of immense help to the spies to transmit prior secret information about the enemies' activities, etc to his kingdom.  The first mail was  carried 
on January 7, 1785 through on a hot air balloon flight from Dover to France near Calais. It was flown by Jean-Pierre Blanchard and John Jeffrey. The letter was written by an American Loyalist William Franklin to his son William Temple Franklin who was  a diplomat in Paris with his grandfather Benjamin Franklin. On January 9, 1793, from Philadelphia to Deptford, New Jersey, Jean-Pierre Blanchard carried a personal letter from George Washington to be delivered to the owner of whatever property Blanchard happened to land on, making the flight the first delivery of air mail in the United States. The first official air mail delivery in the United States took place on August 17, 1859. John Wise piloted a balloon from  Lafayette, Indiana,  to  New York. Weather  conditions forced him to land in Crawfordsville, Indiana,  however,  the mail reached its final destination via train. In 1959, the U.S. Postal Service issued a 7 cent stamp commemorating the event.
First airmail service. British India. between Allahabad and
Balloons also carried mail out of Paris and Metz during the Franco-Prussian War (1870), drifting over the heads of the Germans attacking  those cities.  Hot-air balloons   carried mails successfully and fortunately the weather was quite favorable.  In 1877 balloon mail was also carried on a flight in Nashville, Tennessee. It was in 1903 interest was shown to use the airplanes to run the mail services. An unofficial airmail flight was  operated for the first time
old airmail postal stamp, british India.
by Fred Wiseman and he  carried three letters between Petaluma and Santa Rosa, California, on February 11, 1911. Allahabad cover flown on the world's first aerial post in 1911

 You will be surprised to know that the colonial India was an experiment field for many new ideas. The important event was world's first airmail flight.
It happened at a large exhibition in the United Provinces of Agra and Oudh, British India. One Sir
Fred Wiseman, organizer of the aviation display, got special permit from the Post Master general of British India  to operate an airmail service in order to generate publicity for the exhibition and to raise money for charity. It was in the Holy Trinity Church the mails were collected and the very first airmail flight took off the ground with one Henri Pequet in the cockpit. He carried with him a huge bag containing as many as 6500 letters, etc a whooping number and covered a distance of just 13 km (8.1 mi) from from Allahabad to Naini - the nearest station on the Bombay-Calcutta line to the exhibition. An interesting feature is all letters bore an official frank "First Aerial Post, U.P. Exhibition, Allahabad. 1911". The short distance was covered in thirteen minutes; the aircraft used was a Humber-Sommer biplane.  The plane took off the exhibition around 5.30 PM ( February 18, 1911) made couple of circles, crossed the
Jamuna river and headed for the chosen destination - Naini. The aircraft flew at a height of 130 feet.  It made recorded history and Colonial India was part of it.

So, India had the honor of being the first pioneer country in the world  to carry officially 6500  letters and 40 picture cards, bearing the special cancellations, showing an aircraft  over the mountains surrounded by  script First Aerial Post, U.P. Exhibition, Allahabad. 1911. The second place  in the history of airmail flight was claimed by the UK  on September 18, 1911, eight months later. The letters were carried officially by an  aircraft between Hendon and Windsor - a distance of 10 km.  France became the third country to officially carry the airmail letters on September 13, 1911. They achieved this feat in their Moroccan colonial cities of Casablanca and Fez. The Indian success was mainly due to the efforts of Walter Wyndham who accepted the request from the organizers of the air exhibition in the united Provinces of Agra and  Ouadh. It was Fred Wiseman who specially brought six planes from England to Bombay. Special crates were used to transport the parts. Then from there to Allahabad by train. He also brought two pilots to operate the air aircrafts  one Henri Pequet and the other being Keith Davies, besides two aircraft mechanics. The Champlain of the Holy Trinity church W. E. S. Holland also approached the postmaster general and expressed his desire to help Wiseman raise funds for a boys' hostel. This way the Champlain was indirectly instrumental in introducing the first air-postal system in the vast Indian subcontinent. This led to the birth of world's first airmail service on the Colonial soil of India. The total weight of the letters, etc was around 200  to 300 pounds and this included complimentary mails to many European monarchs, statesmen, officials at Westminster  and people connected to aviation industry world over.