Unless these states meet the minimum security standards outlined by the Real ID Act of 2005 by the deadline of January 22, 2018, those with IDs issued from Kentucky, Maine, Minnesota, Missouri, Montana, Oklahoma, Pennsylvania, South Carolina, & Washington will likely need to a passport even when traveling domestically.
You’re California driver’s license is good, but if you are traveling from an airport in one of those states you can expect backups at airport security.
The TSA already issued extensions from October 10, 2017 to January 22, 2018 for those nine states & more extensions are possible before the changes would take effect.
Also, starting October 1, 2020 the TSA will require a REAL-ID compliant form of identification for domestic travel. For California, it appears we’re all good and compliant with the REAL ID Act so our state-issued driver’s licenses should remain OK. The TSA has more on the deadlines on their website.
For more, head to Travel Skills.