U.S. travelers flying domestically are required to show a Real ID at airport checkpoints. The May 7 deadline for Americans to switch to the federally compliant identification comes after more than 20 years of being delayed.

The time has come. Starting Wednesday, passengers nationwide must a use state-issued ID or license that is “REAL ID” complaint to travel within the US.

Standard ID cards, which are still valid for all other purposes outside of domestic flights and entering federal buildings, now feature the phrase “Not For Federal Purposes” in the top-right corner. Those who wish to obtain a Real ID must go to a DMV office. You cannot get a Real ID online, by phone, or through mail.