The REAL ID Act, which was passed by Congress in 2005, enacted the 9/11 Commission’s recommendation that the federal government enhance security standards for identification.

Passengers at U.S. airports must now show federally compliant IDs to board domestic flights. Don’t have one, or not sure if you do? Here’s some guidance.

Watch an explainer about REAL ID from PBS News in our video player above. Starting May 7, your license or identification card will need to be REAL ID-compliant to fly domestically in the U.S.