Those without the required document are passing through security easily, after receiving information on how to update their IDs.
Know to arrive early before you go
The Transportation Security Administration warned people who don't have the Real ID to show up early and be prepared for advanced screening to avoid causing delays.
"I do not have a belief that this will cause people to miss their flights if they take that additional time in," said Thomas Carter, the TSA's federal security director in New Jersey. "I think there's that self-responsibility of the law that they need to know, give themselves that extra time, and if they do that, they shouldn't have an issue."
Across the country, government offices extended their hours to help meet the demand. But despite that, some people waited for hours Tuesday to get a Real ID ahead of the long-delayed deadline.
Renel Leggett, a college student from West Chester, Pennsylvania, spent hours getting her Real ID and was not happy about it.
"I've been out here for three hours to get one ID when I've already had one that should have lasted me until about 2029," Leggett said. "You have to do it. But it feels like a waste of time," she said.
More secure identification
Real ID is a federally compliant state-issued license or identification card that Homeland Security says is a more secure form of identification. The recommendation for the new IDs came from the 9/11 Commission and was signed into law in 2005.
The commission recommended the government set security standards for state-issued driver's licenses and IDs. It was supposed to be rolled out in 2008. But the implementation has been delayed repeatedly.
Besides needing a Real ID to fly domestically, people will also need one to access certain federal buildings and facilities.
In recent weeks, Noem has been warning the American public about the upcoming deadline. In a television ad put out by Homeland Security, she warned that these IDs were needed for air travel and for entering public buildings, adding: "These IDs keep our country safe."
A Real ID-compliant driver's license has a symbol (in most states, a star) in the top corner of the card.