A Port Authority spokesman says a crane loaded the plane onto a flatbed truck and took it to a hangar before both the airport's runways were reopened.
The nose gear collapsed when Flight 345, coming from Nashville, Tennessee, landed at 5:40 p.m. Monday.
The Port Authority says there were 143 passengers and six crew on board at the time. Ten passengers were treated at the scene, and six were taken to the hospital with minor injuries.
The airport was closed for more than an hour before one runway was able to reopen. More than 350 flights have already been canceled for Tuesday, and arrival delays of more than two hours were being reported.
The NTSB released some findings on Tuesday evening saying:
-The emergency escape slides on Southwest 737-700 deployed normally during LaGuardia accident.
- Southwest 737 slid 2175 feet on its nose on LGA runway before coming to rest, off to the right side of Runway 4.
- Southwest 737's nose gear collapsed up and into the fuselage, damaging the electronics bay that houses avionics.
A passenger, Sgt. 1st Class Anniebell Hanna, 43, of the South Carolina National Guard, said the flight had been delayed leaving Nashville. Passengers had heard an announcement saying "something was wrong with a tire," she said, waiting in a room at LaGuardia several hours after the incident.
At LaGuardia, "when we got ready to land, we nosedived," said Hanna. She and some family members were coming to New York for a visit.
"I hit my head against the seat in front of me," she said. "I hit hard."
Emergency crews were seen spraying foam toward the front end of the plane on the tarmac. The Port Authority said the passengers exited the plane by using chutes.
Hanna said she was among the first to get off the plane, and could smell something burning when she got down to the tarmac. The passengers were put on a bus and taken to the terminal, where they were told to make lists of their possessions on the plane in order to get them back.
Richard Strauss, who was on a nearby plane waiting to take off for Washington, said the nose of the plane was "completely down on the ground. It's something that I've never seen before. It's bizarre."
A rear stairwell or slide could be seen extending from the Southwest flight, said Strauss, who owns a Washington public relations firm. His plane, which was about 100 yards from the Southwest flight, wasn't allowed to taxi back to the gate, he said.
Bobby Abtahi, an attorney trying to catch a flight to Dallas, was watching from the terminal and heard a crowd reacting to the accident.
"I heard some people gasp and scream. I looked over and saw sparks flying at the front of the plane," he said.
The incident came 16 days after Asiana Flight 214 crash-landed at San Francisco's international airport on July 6, killing two Chinese teenagers; a third was killed when a fire truck ran over her while responding to the crash, authorities said. Dozens of people were injured in that landing, which involved a Boeing 777 flying from South Korea.
Longtime pilot Patrick Smith, author of "Cockpit Confidential: Everything You Need to Know About Air Travel. Questions, Answers, and Reflections" and AskthePilot.com, said landing gear incidents are not high on the list of worries for pilots.
"It doesn't happen very often but I need to emphasize just how comparatively minor this is and how far, far down the hierarchy it is," he said. "From a pilot's perspective, this is nearly a non-issue. They make for good television, but this is far down the list of nightmares for pilots."
The FAA and National Transportation Safety Board are investigating.