The 9mm gun was not loaded, but it was accompanied by a gun magazine containing 15 bullets, the Transportation Security Administration said.
Police took him into custody and confiscated the gun, the TSA said.
This is the airport's seventh gun confiscation this year, the agency said.
The TSA, which didn't identify the man arrested Wednesday, said it "reserves the right to issue a civil penalty to travelers who have guns and gun parts with them at a checkpoint."
"Civil penalties for bringing a handgun into a checkpoint can stretch into thousands of dollars, depending on mitigating circumstances," according to a statement from the agency.
Whether you have a concealed gun carry permit or not, you cannot carry a gun onto a plane, the TSA said.
"Passengers are permitted to travel with firearms in checked baggage if they are properly packaged and declared at their airline ticket counter to be transported in the belly of the plane," the agency added.
"Checked firearms must be unloaded, packed in a hard-sided case, locked, and packed separately from ammunition."
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