Yes, but it was the U.S. who made American the language of airline pilots. English is also considered a substitute, but lets be real here, the two languages really are very different these days. American is a very confusing language to be mixed with English.
Anyway, all airline pilots in the world have to understand and speak fluent American. Period. That would be thanks to the U.S. for inventing the plane in the first place , and thanks again for making it widespread (and i realize that there were some small time inventors of the plane elseware, but they didn't get anyplace with it). And by being the first major airline users anywhere, the American language was already the dominant language among airline pilots anywhere, with England (the other island) as our runner up.
Not to mention the tourist factor. If it werent for the rude American who expected everybody else to speak American, then people would just have to learn french when they went to old Pari (that would be Paris), instead of the French people learing American (which, when the fad was started, was more than acceptable to the countries who were getting all the money for small, worthless trinkets).
And then you also have to include the huge boom in american hype that has taken place throughout so many countries right after WWII. I mean, there are still tons of countries where blue jeans are the biggest thing since Michael Jackson, even today, and lets not forget "rock and roll" which has lost most of its popularity in America, but still gets Micheal Jackson his annual revenue in other parts of the world. That very boom in American culture around the world is also responsible for the large spread of the American language as well. American movies and singers flooded the Entertainment market such as Elvis Presley, or Clint Eastwood. Catch phrases like "Thank you very much", and "Hey Partner" infiltrated themselves into every man woman and child all around the world.
Now, im not saying that America did everything on its own, and certainly im not saying that the popularity of the American and English languages are entirely or even mostly based on the United States's contribution to its dispersment, but don't kid yourself, the United States of America had no small part in the popularity of the English and American language either.
P.S. by the way, I believe that Sentinel said most widely spoken, not most popular. As in: Portugese is spoken in more places than any other language
P.S.S. oh, and thanks to Ancient Gamer for permission to modify and use his Avatar picture. It really was exactly what i had been looking for.