Here’s why some Americans might soon need a passport to fly within the U.S.

Frequent fliers who take international trips know to bring along their passport, but what about just for traveling around the country?

Beginning early next year, the REAL ID Act will tighten requirements to fly, and some states’ driver’s licenses might not make the cut.

Here’s what you should know about the act.

A map of the states, issued by the TSA, reveals which states are compliant with the new ID rules is included in the link.