“El Mariachi” translates to the word “musician.” It originally came from the movie “El Mariachi” which was about a guy who sang romance but nobody liked that about him–but he never cared and continued to sing romance wherever he went and whenever he sang. In Airplane Pt. 2 I think it compares that to the old days of BTS and how they continued to sing their songs wherever they went and didn’t care that people didn’t like them or their songs. In the lyrics it says “Wherever in the world, I will sing” which connects that they won’t care and don’t care about who dislikes their music. That they will continue to share their music and passion with the world.