This is a followup question to one I asked earlier. My Thai wife and I are traveling to Thailand next month. She has both a US passport and Thai passport. When I am filling out the info to buy the airline ticket and I have to identify nationality and provide passport number, which passport and nationality to use? I have a visa for me and since she is Thai, she didn't get a visa as I was told on this site that she should just use her Thai passport upon entering Thailand. I only ask this question to avoid confusion at the airport when we depart and when we return.