Beginning in 2016, residents of four states and one territory in the U.S. will not be able to use their driver’s license as ID on domestic flights. Those states are New York, Louisiana, Minnesota, New Hampshire, and the territory of American Samoa.
The reason for this is the states involved do not require proof of citizenship in order to obtain a driver’s license, or their licenses are not sufficiently tamper-proof.
Back in 2005, an act called the Real ID Act was passed, and is being phased in gradually. The passport requirement will be phased in beginning in 2016 (the exact date has not been announced). It is expected there will be a grace period of several months.
Considering how many U.S. citizens do not have a passport, this could possibly lead to some surprises at the airport, not to mention the possibility that the passport offices might be overwhelmed with applicants, leading to long delays in issuing passports.