The judge ruled that "the mask mandate exceeds the CDC's statutory authority."
The ruling came as airlines lobby for an end to the mandate, which had recently been extended to May 3 by the CDC, citing the effectiveness of its air filtration systems and the stress on flight attendants who have had to enforce the rule.
Though the CDC still recommends masks be worn, TSA will no longer enforce the practice. The ruling from the Florida judge concluded "the Mask Mandate exceeds the CDC's statutory authority."
"And on top of that, she said that it was arbitrary in reaching its decision. And it didn't give sufficient reasoning for its decision, so she really hit this mandate in multiple different ways," said ABC7 Legal Analyst Gil Soffer.
"We are not making any immediate changes to the mask requirement while we assess the situation," Metra officials said in a statement after the ruling.
South Shore Line initially said they would also require masks, but changed course and released a statement later Monday night saying they would not be requiring passengers to wear masks when riding their trains.
READ MORE: Florida judge voids US COVID-19 mask mandate for planes, public transportation
"Masks are still required on CTA trains and buses. If that requirement changes, we will notify customers," said a statement issued by CTA.
Doctor weighs in on masking, encourages vaccination as judge strikes down mandate
"The CDA will continue to follow, observe and enforce all current and future guidance by federal, state and local health and security authorities," the Department of Aviation said in a statement.
The flight attendants union is urging patience and calm in the wake of the decision.
"What people want is normalcy and certainty. In some ways, we're going to be in a halfway house for a few weeks, and that could be emotional for lots of people," said Professor Joe Schwieterman, DePaul University aviation professor.
While CTA, Metra and the CDA still require face coverings, many airlines, including United, American and Delta, are already lifting the mandate for passengers and employees in airports and on all domestic flights. They will also not require masks on international routes unless the arrival country requires them.
Travelers at O'Hare learned of the ruling while checking in for their flights.
"Part of me is excited to see a new normal unfold, but also it's still a little bit unnerving coming out of two years of having them. It's kind of like a safety blanket on," said Elayna Karolevitz, passenger.
"And I think people are just so tired of wearing masks, and so I think it's a good idea," said Itelvina Williams, traveler.
"I'm a little bit dumbfounded by it because I still think there's plenty to be caught on airplanes," said Kathleen Kreiman.
Many Monday night remained reluctant to immediately take off the mask.
"I don't think it's too premature, but I'll hold off for my own personal..." said Erick Von Kondrat, traveler. "For a little while longer, yeah."