
Shahzad will appear in a Manhattan federal courtroom Tuesday to face formal charges in the case.
Shahzad was on board Emirates Flight 202 to Dubai, United Arab Emirates, and the jetway had been pulled back when the plane was called to return to the gate, a law enforcement source said. Shahzad was booked through to Islamabad, Pakistan via Dubai, a senior airline official confirmed.
"They just caught him at the last second," a law enforcement source said.
Security officials removed three passengers from the flight late Monday, including Shahzad -- who was taken into custody, the senior airline official said.
Authorities searched the plane, luggage and checked all passengers again before the flight took off for Dubai early Tuesday without the other two passengers taken off with Shahzad, the airline official said.
Police have been engaged in a furious manhunt in the New York area for those responsible for an intended terrorist attack Saturday night in the heart of Manhattan's Times Square.
According to a source familiar with the investigation, the individuals didn't have the expertise to detonate a parked Nissan Pathfinder containing propane tanks, fertilizer and gasoline.
Authorities focused on Shahzad when they traced evidence to him from the sale of the Nissan Pathfinder used in the failed attack -- information considered the linchpin of the case.
The Nissan Pathfinder had its vehicle identification number removed from the dashboard. Police climbed under the SUV and retrieved the VIN from the bottom of its engine block.
This breakthrough led investigators to the registered owner of the vehicle and then to Shahzad, who purchased the SUV, the official said.
The Nissan Pathfinder had been sold three weeks ago in a cash deal with no paperwork exchanged, a law enforcement source with knowledge of the investigation said Monday. The $1,800 deal was closed at a Connecticut shopping mall, where the buyer handed over the money and drove off, the source said.
With memories of the September 11, 2001, attack fresh in the minds of police, detectives pored through video cameras of Times Square and worked to determine who carried out the action -- international terrorists, a lone individual or other networks.
John Brennan, President Obama's top counterterrorism adviser, kept the president abreast of the probe throughout Monday and informed him of Shahzad's arrest early Tuesday, the White House said.
New York Mayor Michael Bloomberg issued a statement praising the 48 hours or so "impressive" law enforcement spadework.
Hours after the arrest, police were seen at a house in a Bridgeport, Connecticut, working-class neighborhood as part of the investigation. Agents with the FBI and local police, including members of a bomb squad, conducted a search, and investigators removed filled plastic bags.
Another law enforcement source said Shahzad claimed to have acted alone in the attempted bombing, but the Joint Terrorism Task Force investigating the bombing attempt has said it's considering the possibility that the attempt involved more than just a "lone wolf."
While police continued to piece together information about Shahzad, they learned he traveled to Dubai before, most recently in June 2009 and returned to the United States in early February, a law enforcement official said.