Trespassers were spotted near airport grounds just as Netanyahu arrived at the airport Saturday night for his flight back home, the New York Post reported.
The alert triggered a massive air and water search of the airport perimeter by the New York City Police Department, the Port Authority and other agencies, authorities said.
In the end, the trespassers turned out to be fishermen, sources told the newspaper.
"It's another major breach of security," one law enforcement source said. "Luckily they were only fishermen and not terrorists."
The fishermen were charged with trespassing.