(David Goldman ~ Associated Press)
The scare was over in a few hours, but it disrupted travel plans for thousands of people as flights were postponed and vehicle traffic to the airport was briefly halted. Delays also rippled across the country as airlines adjusted their schedules.
Authorities identified the man as Scott McGann, a 32-year-old who was apparently homeless and had been living on New York City's streets for at least a year.
He had a ticket for a United Airlines flight headed to Chicago, with connecting flights that would have ultimately taken him to Oakland, Calif., where he has family.
A relative purchased the ticket, said John Kelly, a spokesman for the Port Authority of New York and New Jersey.
McGann faces charges including placing a false bomb in a transportation facility and making terroristic threats.
The trouble began shortly after 5 a.m., when he checked in for his flight and immediately began attracting attention because of bizarre behavior.
Police received two calls about an apparently intoxicated or suspicious passenger before he had even reached a security checkpoint, Kelly said.
Security officials said he was "just acting crazy," Kelly said.
Authorities stopped McGann, but he didn't respond to questions. He then appeared to depress some sort of makeshift trigger, prompting Port Authority police to move in and snatch the bag away.
A search of the duffel turned up an assemblage of batteries and wires that police thought was intended to look like a bomb, Kelly said. An NYPD bomb squad used a high-powered water cannon to blow the device apart.
The terminal was evacuated at around 5:30 a.m. Investigators quickly determined that the device wasn't dangerous, but travelers became inconvenienced as flights were postponed and traffic backed up outside. Passengers didn't get back in to the terminal until close to 9 a.m.
LaGuardia handles about 70 flights per hour, both departures and arrivals.
Roughly a half-dozen United flights were delayed because of the incident, airline spokesman Rahsaan Johnson said. Of the arrest, he said, "We are cooperating with authorities."
American Airlines canceled 16 departing and arriving flights. Delta Air Lines Inc. has a separate terminal from where the incident occurred, so planes continued to arrive and depart, but flights were still disrupted because traffic prevented flight crews from getting to the airport, airline spokesman Carlos Santos said.
Discount carrier AirTran Airways canceled two flights and delayed about a dozen others, spokesman Christopher White said.
"The planes that go to LaGuardia will be delayed the rest of the day I'm sure," he said.
Among the delayed fliers were 12-year-old Samantha Casady and her 10-year-old brother, Patrick, of Norwich, Conn., who were supposed to fly to Dallas at 7:15 a.m. by themselves to visit relatives.
Their mother, Colleen, said she and her husband were accompanying their children through a long security screening line when there was a commotion "and just a swarm of TSA."
Casady said she later saw a man in handcuffs, surrounded by police.
The family was initially directed to go to another security gate, but it was closed, "and a few minutes later, they evacuated the building," she said.
The evacuation also meant that Irma Quidore, of Denville, N.J., had to delay a trip to Monterrey, Mexico, for a second time with her two daughters, Sofia, 6, and Isabella, 3.
They had originally planned to fly out on Thursday, but a delay that would have forced them to miss a connecting flight prompted them to reschedule their trip for Saturday, Quidore said.
"I guess we're going to make the trip to Mexico, but a little bit late," Sofia said as she pushed her little sister in a stroller toward the terminal.
McGann remained in police custody Saturday afternoon. He has been arrested in the city at least three times previously in the past two years, most recently in June, authorities said.
Associated Press writers Colleen Long and Amy Westfeldt in New York and AP Airlines Writer Harry R. Weber in Atlanta contributed to this report.