All pilot and air-traffic control communications are in English. This simplifies interaction in an arena where mistranslation and misunderstanding could prove catastrophic.
In the air, the preferred alphabet is one of words, rather than individual letters. Not only do letters like "j" have a different pronunciation in Spanish ("h") and Portuguese ("zh"), but radio waves are not always clear. Did you say "m," or was that an "n?" "D" and "b," too, could be easily confused.
Although the beginnings of a solution began to emerge during the First World War, individual implementations remained the rule of the day. The British Royal Navy began their alphabet with "Apples," "Butter," and "Charlie," whereas the British infantrymen in the trenches uses "Ack," "Beer," and "Charlie."
We all share the skies. In 1927, a standardized "International Radiotelephony Spelling Alphabet" (also known as the ICAO phonetic alphabet) was created to help aircrews around the world communicate their names and locations:
Alfa, Bravo, Charlie, Delta, Echo, Foxtrot, Golf, Hotel, India, Juliett, Kilo, Lima, Mike, November, Oscar, Papa, Quebec, Romeo, Sierra, Tango, Uniform, Victor, Whiskey, X-ray, Yankee, Zulu.
As with letters, the pronunciation of numbers is also standardized. The number nine is pronounced "niner," four is "fower," and five is "fife." The explanation for this is that "nine" is the well-known German word meaning "no," "four" can be mistakenly understood as a proposal "for," while "five" can be mistaken for "fire" (a fire or an order to shoot).
In 1927, too, the Kingdom of Yugoslavia founded Aeroput, among the first European airlines. The company, which in post-World War II Yugoslavia became JAT/ Yugoslav Airlines ("Jugoslovenski Aerotransport"), is now Air Serbia.
A version of this story appeared in Air Serbia's "Elevate" in-flight magazine in March. The company this year shares a ninetieth birthday with its industry's alphabet, making it the eighth oldest surviving airline in the world.