The rest of the airport stayed open while the bag was checked.
The black briefcase-type bag apparently had almost nothing in it, Coleman said. The bag's owner was en route to San Francisco, Coleman said.
"Out of an abundance of caution, the check-in area and security checkpoints were closed," the Transportation Security Administration said in a statement.
A Port Authority police K-9 unit and an NYPD bomb squad responded. Police "determined the item and its contents were not harmful," American Airlines said in a statement.