A stand-off at New York's John F Kennedy International Airport has ended after the gunman gave himself up.
The gunman had earlier freed the pilot and co-pilot of a jet he had taken hostage.
The pilot had emerged with a list of demands, including the man's wish to speak with someone from the Argentine Consulate, according to New York Police Chief Thomas Fahey.
It is not clear if his demands have been met.
Witnesses say the gunman had earlier told a flight attendant to shut the door to the jet before dozens of passengers rushed out of the plane.
The man held a gun to the pilot's head but did nothing to stop the exodus.
Dave Schlesinger, a passenger, saw the commotion as a police officer aimed his own weapon at the cockpit door.
"I didn't know what was going on until I saw that Swat (police commando) team member with a shotgun. Then I knew it was serious," Schlesinger said.
Police say the gunman entered the plane as passengers were boarding a flight to Las Vegas.
Witnesses say the flight had been delayed by fog for about an hour but was ready to take off when the man flashed a gun at airline workers, walked down the jet way, onto the plane and into the cockpit.
It was then that the passengers panicked and ran for the door. At least 40 or 50 escaped.
