(NEXSTAR) — In less than a month, those looking to fly domestically in the U.S. will need a new form of identification: a REAL ID. But what if you don't have a REAL ID by the May 7 deadline?

First, don't panic. You may already have a REAL ID-compliant identification card, or another form of identification that can get you on a plane.

Here's what you need to know about flying with — and without — a REAL ID ahead of the May deadline.

What is a REAL ID?

Congress passed the REAL ID Act in 2005 in light of the 9/11 terrorist attacks, instituting a national minimum requirement for state driver’s licenses and ID cards. States must now at least require proof of your legal name, date of birth, Social Security number, legal residency, and two forms verifying your address before issuing a driver’s license or ID card.

This thereby created the REAL ID-compliant state identification cards.