No, you cannot use a REAL ID alone to fly from the United States to Mexico. While a REAL ID-compliant driver's license (marked with a star in the top right corner) is mandatory for domestic commercial flights within the U.S. as of May 7, 2025, it does not serve as a substitute for international travel documentation. To enter Mexico by air, U.S. citizens are required to present a valid passport or a passport card (the latter is only valid for land and sea crossings). Your REAL ID will get you through the TSA security checkpoint for the domestic leg of your trip, but the airline will not allow you to board the international flight to Mexico without a passport. Additionally, Mexico requires all international travelers to complete an Official Entry Form (FMM), which often requires your passport number for processing. Always ensure your passport is valid for at least six months beyond your intended stay to avoid any issues with immigration officials upon arrival.