A federal law requiring Americans to present a Real ID or another accepted form of identification to fly within the United States will soon take effect following nearly two decades of deadlines and extensions.

With the federal REAL ID deadline quickly approaching, U.S. travelers over 18 will need a REAL ID or another approved form of identification, such as a passport, to board domestic flights starting May 7.

The REAL ID Act was passed in 2005 in an attempt to strengthen national security through increased identification standards, and was originally set to take effect in 2008, but has been delayed numerous times.