Also known as a "knuckle knife," the blade "folds into the handle of the knuckles," Transportation Security Administration Spokesperson Lisa Farbstein said.
The double-edged trench knife was invented for close-quarters combat during World War II, when fighting predominately happened in trenches. The "knuckle-duster" handle was intended to protect the fingers and provide a secure grip, but it also added to force to a blow.
Knives, like guns, are prohibited on planes.
"And brass knuckles are illegal in NYC," Farbstein noted.
The weapon and the traveler were turned over to Port Authority Police.
Click here to follow Daily Voice Elizabeth and receive free news updates.