Ok, I am just so annoyed right now. I am leaving for Puerto Rico soon, and I just contacted travel.gov by phone and they said you only need a license. But on my airline's website, it says you need a passport, so I called them to check that. They said, "Let me transfer you to 'International.'" "Okay," I said, "but isn't Puerto Rico part of the United States?" "Yes, it is. Let me transfer you to international." "Okay..." "Yes, ma'am, you do need a passport." What is going on here??? I find this so absurd. I am getting all this conflicting information. I am bringing my passport just in case, but does anyone know the correct answer to this?