From TSA press release April 4, 2019 (https://www.tsa.gov/news/releases/2019/04/04/tsa-reminds-tra...): "Travelers will begin seeing new signs at airports nationwide in the coming weeks to remind people that REAL ID-compliant licenses or other acceptable forms of ID, such as a valid passport, federal government PIV card or U.S. military ID, will be mandatory for air travel beginning on October 1, 2020. Critically important, on October 1, 2020, individuals who are unable to verify their identity will not be permitted to enter the TSA checkpoint and will not be allowed to fly."