In less than a month, Oregonians hoping to travel by air may find themselves grounded.

Starting May 7, all U.S. flyers must have either a Real ID or a valid U.S. passport to fly domestically.

Oregonians still hoping to get a Real ID card are running out of time. Offices for the Oregon Department of Motor Vehicles, which issues the IDs, are overwhelmed with demand, and officials are encouraging those who don’t need to travel in May or June to wait before applying.

As of Monday, only 36% of Oregonians — about 1.3 million people — have been issued Real ID cards, according to Oregon DMV. Another 1.7 have opted not to get the card when they have renewed their license, leaving about 650,000 people still in need.

But scheduling an appointment at the DMV is difficult. The DMV releases 30 days worth of appointments every day, Crabb said, and people are encouraged to check often.

“If you come in and have an appointment, you can be in and out in 10 to 15 minutes,” said Chris Crabb, a spokesperson for Oregon DMV. “If you don’t, you could be waiting for hours.”

But if you don’t have imminent travel plans, it may be better to wait.

“If you are not planning on flying anytime in the near future, you don’t have to rush out and get it,” she said. “But if you do plan on flying, you will want to get yourself a real ID card.”

Real IDs are intended to make state-issued identification cards and driver’s licenses more secure. Congress approved Real ID plans in the years following the Sept. 11 terrorist attacks as a way to tighten security in U.S. air travel. But the Department of Homeland Security has repeatedly pushed the implementation deadline back from its original 2008 target.

While some states offer Real ID cards for free, Oregon DMV charges a one-time fee of $30, in addition to regular license fees.

After visiting the DMV, Oregonians will be issued a temporary card during the few weeks it takes for their Real ID to arrive. However, the Transportation Security Administration, which oversees airport security, has said those temporary cards will not be accepted as valid Real ID starting May 7.

That means the last day Oregonians can reasonably expect to get their Real ID cards before the deadline is April 16, Crabb said.

Travelers without Real ID cards will still be able to fly, but may face significant delays as TSA workers verify their identity, according to TSA Federal Security Director for Oregon Kathleen McDonald.

“The length of that delay is really determined based on the number of other travelers who don’t  have a Real ID-compliant credential or other form of government ID,” she said.

In place of a Real ID, TSA will also accept a valid U.S. passport or U.S. passport card, a foreign government-issued passport, military ID, permanent resident card, a photo ID issued by a federally recognized Tribal Nation, and other less common forms of ID.

The DMV includes a list of acceptable alternatives for Real ID on its website.

“Even if you don’t have travel plans now, your plans could change. So now is the time to plan what type of photo id you will use when you travel.”