Shanna McLaughlin, 26, was arrested at the Orlando airport before boarding a flight to Los Angeles.
Screeners reportedly found the loaded revolver in her duffel bag. Police said the .45 caliber revolver was loaded with six hollow-point bullets.
McLaughlin told police the gun is her boyfriend's and she didn't know it was in her bag. She has a permit to carry a concealed weapon, but didn't have it on her.
McLaughlin was Playboy's Playmate of the Month in July 2010.
The Associated Press contributed to this report.