The Transportation Security Administration (TSA) has extended the face mask requirement on all transportation networks throughout the United States, including at airports and on commercial flights, as well as commuter bus and rail systems, through Sept. 13.

The order was set to expire on May 11.

People must wear masks “while boarding, disembarking, and traveling on any conveyance into or within the United States” and “at any transportation hub that provides transportation within the United States.”

The rule does not extend to private car travel or commercial trucks being driven by a sole operator.

“The federal mask requirement throughout the transportation system seeks to minimize the spread of COVID-19 on public transportation,” Darby LaJoye, the Senior Official Performing the Duties of the TSA administrator, said in a statement. “About half of all adults have at least one vaccination shot and masks remain an important tool in defeating this pandemic.”

“We will continue to work closely with the Centers for Disease Control and Prevention (CDC) to evaluate the need for these directives and recognize the significant level of compliance thus far,” LaJoye continued.

Penalties for noncompliance begin at $250, under current TSA rules, but could increase to $1,500 for those who repeatedly violate the rule.

Children under 2 years of age and people with certain disabilities are exempt from the requirement.

The TSA said it has received reports of nearly 2,000 people who violated the rule, noting that it has “largely experienced voluntary compliance.”