Defiantly declaring "a day of victory," a Nigerian man was given a mandatory life sentence Thursday for trying to blow up a packed jetliner with a bomb sewn into his underwear. People aboard the flight testified that the failed attack had disturbed their sleep and travels for more than two years.

Umar Farouk Abdulmutallab was the same remorseless man who four months ago pleaded guilty to all charges related to Northwest Airlines Flight 253. He seemed to relish the mandatory sentence and defended his actions as rooted in the Muslim holy book, the Qur'an.

"Mujahideen are proud to kill in the name of God," he said. "Today is a day of victory."

Had the bomb not fizzled, nearly 300 people aboard the flight would probably have been killed.

The case stirred renewed fears that terrorists could still bring down an American jetliner more than eight years after the Sept. 11, 2001 terror attacks, and it accelerated installation of body scanners at U.S. airports.

Before Thursday's sentencing, four passengers and a crew member from the flight told U.S. District Judge Nancy Edmunds that they have struggled to live and travel normally since the incident on Christmas Day 2009.

'Look at me, I’m not afraid.'—Canadian passenger Shama Chopra

During their remarks, Abdulmutallab appeared disinterested, rarely looking up from his seat just a few metres away.

Abdulmutallab "has never expressed doubt or regret or remorse about his mission," Edmunds said. "In contrast, he sees that mission as divinely inspired and a continuing mission."

Life in prison is a "just punishment for what he has done," the judge said. "The defendant poses a significant ongoing threat to the safety of American citizens everywhere."

Son of wealthy banker

Abdulmutallab, the 25-year-old, European-educated son of a wealthy banker, tried to set off the bomb minutes before the Amsterdam-to-Detroit flight landed.

The government says he first performed a cleansing ritual in the lavatory — brushing his teeth and perfuming himself — then returned to his seat. The device didn't work as planned, but it still produced smoke, flame and panic.

He was subdued by fellow passengers and quickly confessed after getting hauled off the plane. He told authorities that he trained in Yemen under the eye of Anwar al-Awlaki, a radical American-born cleric and one of the best-known al-Qaeda figures.

The judge allowed prosecutors to show a video of the FBI demonstrating the power of the explosive material called PETN found in Abdulmutallab's underwear. As the video played, Abdulmutallab, who was wearing a white skull cap and oversized prison T-shirt, twice said loudly, "Allahu akbar," or God is great.

Umar Farouk Abdulmutallab, shown in this December 2009 photo released by the U.S. Marshal's Service, has been sentenced to life in prison. (Associated Press)

Lemare Mason, a Detroit-based flight attendant who helped put out the flames, told the judge that he suffers night sweats and his "dream job" no longer is a "joy."

Passenger Shama Chopra, founder of a Hindu temple in Montreal, left Muslim prayer beads for Abdulmutallab on the defence table after her testimony. She recalled smelling his burning flesh inside the plane's cabin, a moment "that gives me nightmares to this day."

But Abdulmutallab's actions have also made her "bolder and bigger," she said in court.

“Look at me, I’m not afraid.”

Theophilus Maranga, a New York lawyer who was aboard the plane, said he was disgusted by Abdulmutallab's continued references to religion as justification.

"What kind of God is that? God is peace-loving," Maranga said in court, adding that he prays daily for Abdulmutallab.

Bomb-maker killed

Abdulmutallab's mentor, Al-Awlaki, and the bomb maker were killed in a U.S. drone strike in Yemen last year, just days before Abdulmutallab's trial. At the time, President Barack Obama publicly blamed al-Awlaki for the terrorism plot.

Abdulmutallab is an "unrepentant would-be mass murderer who views his crimes as divinely inspired and blessed, and who views himself as under a continuing obligation to carry out such crimes," prosecutors said in a court filing.

Nine members of Abdulmutallab's family travelled to Detroit but did not attend Thursday's hearing. They said they were grateful that no one else was seriously hurt.

In a statement, the relatives said everyone who knew Abdulmutallab thought of him as the "last person" who would attack an airliner for al-Qaeda.

Anthony Chambers, an attorney assigned to help Abdulmutallab, said a mandatory life sentence was unconstitutional punishment for a crime that didn't physically hurt anyone except Abdulmutallab. The government insisted plenty of harm had been done.

"Unsuccessful terrorist attacks still engender fear in the broader public, which, after all, is one of their main objectives," prosecutors said in a court filing before sentencing.

Abdulmutallab's ability to defeat security in Amsterdam spurred the Transportation Security Administration to make swift changes.

The agency was using body scanners in some American cities at the time, but the attack accelerated their placement. Hundreds of the devices are now in use nationwide.

With files from CBC News