Dan, star of YouTube channel Do It With Dan, took to the sky above Tampa to shoot an automatic submachine gun over the Gulf of Mexico and posted his experience online.
Serbu told the Times he circled the Gulf of Mexico between Clearwater and Tarpon Springs for more than an hour before settling on a safe spot a couple miles from shore at an altitude of about 3,000 feet.
Until the Times contacted him Monday, Serbu said he didn't know the video had drawn the attention of authorities.
"There was no one close to us, no one for at least 10 miles," he said.
"We did everything safe. I had my daughter with us."
Valerie Serbu, 22, is the third person on the plane.
The trip was the idea of the show's host — a man identified on YouTube as Dan who says he's 24 and from Atlanta but wouldn't give the Times his last name. His channel specializes in videos of motorcycle and firearms stunts and has over 800,000 subscribers.
"He just thought it would be fun to shoot guns into the water from a plane," Serbu said with a chuckle.
Some of Dan's viewers had negative things to say in the YouTube comments section, so he took the video down last week — but not before someone copied it to send law enforcement. Dan put the video back online Monday afternoon.
Neither Serbu nor Dan could remember the date of the flight. Police learned from personnel at Peter O. Knight that they flew out of the Davis Islands airport Feb. 21.
In 2013, Serbu made national headlines by refusing to sell semi-automatic, .50-caliber rifles to the New York City Police Department because he disagreed with the NY SAFE ACT that classifies the weapon as an assault rifle, banning it from use by the public.