After an uneven rollout that left many scrambling for Department of Motor Vehicles appointments ahead of the long-anticipated enforcement of REAL ID, air travel across the US went smoothly Wednesday — with many passengers opting to use their passports and officials ushering people without REAL IDs to separate lines for enhanced screening.

But with a busy travel season ahead, officials are advising people not to wait on updating their IDs. While 81% of travelers REAL ID compliant, according to the Department of Homeland Security, some states have much lower compliance rates.

Ahead of the rollout, officials stressed that passengers showing up Wednesday without a REAL ID would still be able to fly but “may” face additional screening.

At Atlanta’s Hartsfield-Jackson International Airport, the world’s busiest airport, officials eliminated a separate security lane mid-morning Wednesday because so few travelers lacked a REAL ID. Staff at North Carolina’s Charlotte Douglas International Airport had extra security lanes and staff ready, but travelers mostly had the identification they needed and moved smoothly through security, a CNN crew observed.

“The traveling public was great, they responded, they were prepared, everything went as well as it could be expected,” said Gerardo Spero, the Transportation Security Administration’s federal security director for Pennsylvania and Delaware.

Though Wednesday was the date the new requirement for air travel went into effect, it left many confused travelers scurrying to comply ahead of the upcoming holidays and summer months.

At airports across the country, signs about the REAL ID requirements were posted asking, “Are you REAL ID ready?”

In some airports, those without a REAL ID or acceptable alternative, such as a US passport, were ushered to separate lines for enhanced screening. Travelers were also given a warning to expect delays the next time they travel if they don’t present a REAL ID or another acceptable form of identification.

REAL IDs are marked with a star, no matter what state you live in, and travelers can find out if they have a REAL ID by using the TSA’s interactive tool.

The 9/11 Commission recommended the new standard for enhanced security. Enforcement of the 2005 REAL ID Act law was pushed back several times.

The 20-year-old law requires state driver’s licenses to meet certain federal requirements to be used for boarding a plane or accessing federal facilities requiring identification. The enhanced features in a REAL ID include anti-counterfeiting technology.

With a busy travel season ahead, officials are advising people not to wait on updating their IDs.

Jana Tidwell, with AAA Mid-Atlantic, is urging those who don’t have REAL IDs to get them now, so they aren’t hit with delays or other issues during peak travel times. “We are just a couple weeks away from Memorial Day, the unofficial start of summer. Summer travel is going to ramp up,” Tidwell said.

That may be more critical in states with low compliance with REAL ID requirements. In Illinois, compliance is below 50%, Max Walczyk, spokesperson for Secretary of State Alexi Giannoulias, told CNN.

Alabama had only 33% REAL ID compliance, while North Carolina’s REAL ID compliance was at 52%, officials said.

“It’s going to be important for those without REAL ID to go ahead and make an appointment with their state DMVs to obtain a REAL ID as early as possible, because the requirement is still very much in effect,” a TSA spokesperson said.

As for whether there will come a time that people without acceptable forms of ID will be turned away, the TSA hasn’t said.

“We’re working with states, airlines and airports collaboratively toward a closer to 100% compliance rate,” the spokesperson said. “REAL ID is here, and it’s important for passengers and travelers to obtain one.”