A totally US flight should still be no problem. The problem is that at present you can't book a one way international flight from outside the country using a US credit card ONLINE. You have to call them and have them do it on the phone. And as in my case, potentially they tell you the fare has gone up, or it's more points, or the taxes aren't what it shows online. The first time I called, the supervisor I was eventually routed to just said it wasn't their problem, they couldn't do anything about the taxes, which didn't set well. The second time I called the person wasn't a supervisor as far as I know, but she understood the issue and worked until she fixed it. The SECOND person did provide good customer service.