Every since the invention of flight, this modern and rapid means of transport has continued to grow in importance - including for the conveyance of mail.
It was during the First World War that the army first began to use aircraft to transport field post. Thanks to the aircraft, the Ukraine in particular, then occupied by German and Austro-Hungarian troops, was brought closer for telecommunications purposes by an air route. The Vienna-Krakow-Lvov-Kiev route was approx. 1,200 km in total in one direction, and after a trial flight, it was initially only used for the most important military, diplomatic and service mail. The line was flown by Hansa Brandenburg C 1, Oeffag C II and Albatros aircraft. Once these flights had proven successful, the postal administration began using the route for private letters and telegrams on March 31, 1918, although only as far as Lvov to being with. The entire route to Kiev was opened to private post from the beginning of July of the same year. The flight took place in stages, the total flying time amounting to around 11 hours.
In this way, air mail was invented, the first air mail stamps were issued and a new field for philatelists was borne.
The stamp shows the loading of mail bags onto an Oeffag C II. This aircraft was built in Austria at the Osterreichische Flugzeugfabrik AG (Oeffag) constructed in 1915 in Wiener Neustadt. The Oeffag C II biplane had a top wingspan of 12.93 m and a bottom span of 12.04 m, was 8.64 m long in total and designed for a two-man crew.