Passengers on board two Delta flights at Kennedy Airport were taken off each of the aircrafts Monday night as authorities investigated a bomb threat that turned out to be unfounded, officials say. An anonymous phone call was placed to Delta headquarters just after 6 p.m. suggesting a pipe bomb was on Delta Flight 468, according to Port Authority spokesman Joe Pentangelo. There are two Delta flights with the number 468: one has a Boeing 757 plane landing at JFK from San Francisco at 8 p.m., with 171 passengers on board, according to Delta Airlines.The other flight has a Boeing 777 plane leaving JFK at about 9:30 p.m. to go to Tel Aviv, with 215 passengers on board.It appears the threat was referencing the incoming flight from San Francisco, but both flights were searched out of an abundance of caution, said Pentangelo. The Tel Aviv-bound plane was still on the tarmac when the threatening call was placed, law enforcement officials said. It was searched and cleared, and took off on or close to schedule.The plane arriving from San Francisco was still in the air at the time of the threat. It was evacuated when it landed at JFK, and law enforcement executed a K-9 search of the aircraft and baggage area.Passengers were ordered to leave everything on the plane as it was evacuated, including carry-on bags, according to passenger Austen Holman, 29. They were only allowed to take their phones with them, which they were forbidden to use until they arrived at the terminal.There was no evidence to suggest the threats were legitimate, but law enforcement responded per emergency protocol out of an abundance of caution, officials said. Waiting to recover luggage after being taken by bus to the terminal Monday night, Holman told NBC News over the phone that “everyone’s been pretty calm and well-behaved.”The plane was cleared and set to return to the gate late Monday night where passengers were able to retrieve their luggage.