Man who threatened passengers on Frontier flight with box cutter sentenced to prison

An Ohio man has been sentenced to more than two years in prison for threatening passengers on a Frontier flight with a boxcutter and causing the plane to make an emergency landing at the Atlanta airport.

Officials say on Nov. 11, 2022, 43-year-old William Allen Liebisch arrived at the Cincinnati airport to take a flight from Ohio to Tampa, Florida. 

While passing through the TSA security checkpoint, authorities say officers took a box cutter that Liebisch had in his possession. The TSA agents believed that they had disabled the tool by removing the blade, but officials say during the flight, Liebisch inserted a spare blade that had been stored in the box cutter's handle.

According to information submitted in court, a passenger spotted Liebisch holding the box cutter. Another passenger told flight attendants she heard him make a threat to the people onboard the plane. 

"The lady came up and told us that the person sitting to the right of her seat had a weapon and showed it to them and said he was going to cut multiple people on the flight," passenger Larry Cumberbatch told FOX 5 in 2022.

Cumberbatch, a US Navy veteran, said that crew members tapped him and another former member of the military on board to help subdue the suspect if anything escalated. So, they came up with a plan for him to switch seats with the woman who notified flight crew members about the threats.

"He has a weapon and I don’t know what kind of weapon it is ... I said, ‘Hey I’m gonna be sitting here from now on’ and he said ‘No, the young lady is gonna be sitting there’… He got like frantic, and he said ‘Oh no!’… and then he got up and went to the back of the plane," Cumberbatch explained. 

While the men and crew tried to keep the situation under control, the captain decided to make an emergency landing at Hartsfield-Jackson Atlanta International Airport.

Cumberbatch says Liebisch refused to deplane and then walked toward flight attendants with his hands in his pockets. That’s when another man, with a background in law enforcement, tackled him.

"He was concerned his movements were gonna go toward them and harm them … He just grabbed him, bear-hugged him, and they fell," Cumberbatch said. 

Atlanta police arrested the suspect. Cellphone video obtained by FOX 5 showed police taking the man into custody. 

"The flying public deserves to travel in peace without fear that a fellow passenger will create a violent disturbance," said U.S. Attorney Ryan K. Buchanan. "Liebisch’s conduct created panic among the flight crew and his fellow travelers. His prosecution and sentence hopefully provide a message of deterrence to others."

Liebisch pleaded guilty to interfering with the performance of the duties of a flight crew on Dec. 14, 2023. This week, a judge sentenced him to 30 months in prison followed by three years of supervised release.