"Jet" was the name of a black Labrador that Paul McCartney and his wife Linda owned, and the dog provided the title for the song. The McCartney's owned a variety of animals, and at the time their brood included a Golden Lab named Poppy, a Dalmatian named Lucky, and the old Sheepdog Martha (from the Beatles song "Martha My Dear
"). "Jet" was chosen not because he was Paul's favorite, but because the name makes a very stadium-ready title, perfect for throwing your fist in the air when it's performed in an arena. The song is really about freedom; McCartney did something similar when he used an amusement park ride as the title for a song about madness in "Helter Skelter
Paul's wife Linda gave some clues to the thought process behind "Jet" when she said in 1976: "He wanted that one to be totally mad. Paul's had a lot of practice in the studio. He's done some very trippy things. Every now and then he remembers how much he loves it."