Time to pay up if you fly without a REAL ID or an accepted alternative.

Effective Sunday, Feb. 1, travelers lacking REAL ID-compliant identification must pay a new $45 fee to have their identity verified through the Transportation Security Administration's new ConfirmID program.

"All travelers 18+ will need to pay the $45 fee for TSA ConfirmID to attempt to have their identities verified. The fee goes towards the cost of the alternate identity verification, which until now has been shouldered by the taxpayers as a whole," TSA told USA TODAY by email. "The two options are to have a REAL ID or an acceptable ID, or to pay the $45 fee to participate in TSA ConfirmID. There is a not a free option."

Travelers have been required to present REAL IDs or other acceptable identification at airport security checkpoints since last May, when the REAL ID Act took full effect, after years of advance notice.

"It's the law, and this law has been effect since 2005," Acting Executive Assistant Administrator for TSA Steve Lorincz said in a video the agency shared with news media. "It's one of the recommendations from the 9/11 Commission. ID verification is critical to TSA and critical to TSA's layered security approach process. So for us, our security and safety is paramount, and this is one of those layers that is critical to make sure that the system is safe."