The nine states are Kentucky, Maine, Minnesota, Missouri, Montana, Oklahoma, Pennsylvania, South Carolina, and Washington. Each of these states does not currently issue a state ID that lives up to federal ID minimum security requirements, according to the REAL ID Act of 2005. That means these states have about three months to make changes to their state IDs or drivers licenses so that they meet federal government standards. Otherwise, you'll need to apply for or renew a passport—or at the very least, find yours, wherever you stashed it after the last trip—before passing TSA and getting on a commercial airplane to another U.S. city. 

 Other forms of ID that will work are permanent resident cards (green cards) or military IDs. As Forbes reports, some states are in the process of updating their ID situations before January 22, so that you might not need a passport to fly—check with your local government for updates. It also looks like even more states will fall under the TSA's flight restricted category by 2020. 

Moral of the story: It takes four to six weeks to get a passport request processed, so it wouldn't hurt to start planning ahead now. 

 From: Esquire