Starting May 7, 2025, all travelers aged 18 and older must present a REAL ID-compliant form of identification (or another acceptable form of identification) to board domestic flights within the United States.
A REAL ID is a state-issued driver?s license or identification card that meets federal security standards, usually marked with a star in the upper portion of the card.
For domestic flights, acceptable forms of identification include a REAL ID-compliant driver's license, U.S. passport, DHS Trusted Traveler cards, and more.
More information as to what identification is accepted is available on the TSA's site.