If somehow the calendar could be spun forward one year, and today were Oct. 2, 2020, not 2019, around 99 million Americans would be ineligible to get aboard commercial airlines. And almost three out of every four Americans would lack any acceptable form of identification needed for air travel.

Thankfully, it’s still 2019, so the 235 million to 240 million of us who do not now possess a “REAL ID” compliant driver’s license still have 365 days, until the Oct. 1, 2020 deadline (2020 is a leap year, so there’s one extra day in it) to get one.

But that brings up two hugely obvious questions: What is a REAL ID? And, why do I need one?

You can thank Congress, circa 2005, for this new requirement. Back then, in the aftermath of the 9-11 terrorist attacks, Congress was seeking to increase the level of aviation security in a variety of ways. We all became acutely aware of the heightened level of security screening at airport entries. The government also began keeping various watch lists of known or suspected troublemakers who were not – and still aren’t - allowed to board airline flights in or to this country. We also heard all about the installation of bullet proof cockpit doors meant to keep bad guys from commandeering aircraft ever again. We even became aware of rule changes that allow pilots who volunteer for firearms training to be armed in the cockpit as a last line of defense.

Most of us, however, missed the passage of the REAL ID Act requiring all Americans boarding flights to have a REAL ID-compliant form of identification. Phase III of that Act, the phase where the requirement becomes universal within the 50 states, takes effect next October 1. And the primary form of REAL ID compliant identification will be state-issued drivers’ licenses.

Problem is, few states have begun issuing REAL ID-compliant, or enhanced licenses. Thus, approximately 72% of Americans do not yet have REAL ID compliant driver’s licenses. There are other forms of REAL ID-compliant identification that will work in lieu of a REAL ID-compliant driver’s licenses – most prominent among them being a passport. But an estimated 99 million American do not possess a passport either, plus most people traveling domestically don’t carry their passports on such trips.

Children under 18 won’t be required to have REAL ID compliant identification if they are traveling with an adult who does have such ID.

Though a full year remains until the REAL ID requirement takes full effect, it’s likely that some number – perhaps a relatively large number – of Americans still won’t have their REAL ID-compliant identification by the deadline. As a result, they won’t be allowed to fly until they do obtain such ID. And that, potentially, could have a large economic impact on the nation.

The U.S. Travel Association, a non-profit that promotes travel too and within the United States on behalf of the broad spectrum of travel and tourism businesses, calculates that were the REAL ID requirement effective today at least 78,500 travelers a day would be turned away at Transportation Security Administration checkpoints at airports all around the nation. That would cost the U.S. economy an estimated $40.3 million in lost travel-related spending per day. And if that trend were to be sustained for a full week, those numbers would grow to more than half a million air travelers being blocked from flying and around $282 million in lost travel spending.

Obviously, many Americans will be getting their REAL ID-compliant licenses and/or other compliant identification before the Oct. 1, 2020 deadline arrives. But it’s likely that not all will, so some degree of reduced traveler totals and reduced travel spending will manifest itself in the first few weeks after the deadline next October.

So, what do Americans need to do so that they’ll be allowed to fly after Oct. 1 next year?

All 50 states now are signed up to the REAL ID program and will begin at some point this year issuing REAL ID-compliant driver’s licenses. When those licenses will become available varies by state, so individuals will need to check with their state licensing agencies to find out when and how they can get a REAL ID-compliant license. The USTA is urging people not to wait to get their REAL ID-compliant driver’ license so that state licensing agencies won’t get overwhelmed and bogged down by a deluge of requests for new driver’s licenses next summer as the deadline approaches.

Such licenses will feature a special mark, typically in the upper right corner of the license. The marks vary by state but typically will include a gold or black star, or a gold or black circle with a white black star inside the circle. Some states will be issuing cards marked with their state emblem or an outline of the state with a gold, black or white star incorporated in it.

Obviously, if your driver’s license is scheduled to be renewed or re-issued between now and Oct. 1, 2020, you’re due for a new license to be issued to you, and there’s a very good chance you’ll be issued one with the REAL ID markings on it. But if your current driver’s license isn’t scheduled to be replaced within the next year, or if it is but that date comes before your state starts issuing its REAL ID-compliant licenses, you’ll need to contact your state’s licensing agency about how to get the kind of license you’ll need.

Some federal agencies and installations – like military posts and government buildings – also are subject to the REAL ID identification rules beginning next October.

There are also other forms of ID that are REAL ID-compliant for those who don’t have or need a driver’s license. U.S. passports are the most obvious alternate type of ID that are REAL ID-compliant. Other compliant IDs include: U.S. passport cards; Department of Homeland Security trusted travel cards used as part of the Global Entry, NEXUS, SENTRI and FAST programs; U.S. Department of Defense ID cards issued to military members and their dependents; permanent resident cards; border crossing cards; federally recognized tribal-issued photo IDS; HSPD-12 PIV cards; passports issued by foreign governments; Canadian provincial driver’s licenses or Indian and Northern Affairs Canada ID cards; transportation work identification credentials; U.S. Citizenship and Immigration Services Employment Authorization cards (I-766); or a U.S. Merchant Mariner Credential.

U.S. Travel also is seeking changes to the program to help ease the transition for American travelers. Among the policy changes being sought are:

* Amend the REAL ID Act to allow Americans to apply online and via mobile devices for REAL ID identification documents, and to permit TSA security screeners at airports to accept mobile or digital REAL ID-compliant driver’s licenses. That, USTA says, should help reduce any backlogs in issuing compliant driver’s licenses and will improve airport checkpoint efficiency

* Designate registered traveler enrollment as an acceptable alternative for obtaining a REAL ID driver’s license or other acceptable form of compliant ID. That would allow the TSA to use the existing security and identification features of trusted traveler programs, including TSA Precheck, to reduce the need for a REAL ID Act-compliant driver’s license at airport checkpoints

* Transition TSA checkpoints to automated identity verification. That would accelerate the implementation of automated identity verification technology used by passport holders and trusted travelers. In addition to strengthening security and improving checkpoint efficiency, the USTA argues that doing so would decrease the number of travelers who arrive at airport checkpoints REAL ID-compliant identification

* Develop alternative screening procedures for travelers who lack compliant ID in order to avoid turning away large numbers of travelers who appear at checkpoint without compliant ID