Mr Abdulmutallab's court appearance lasted less than five minutes
A "not guilty" plea has been entered on behalf of the Nigerian man accused of attempting to detonate a bomb on a Detroit-bound plane on Christmas Day.
A Detroit judge took the action after Umar Farouk Abdulmutallab declined to enter a plea during his first court appearance.
Mr Abdulmutallab, 23, is charged with the attempted murder of 290 people and five other counts.
The incident has led to dozens of new security measures being introduced.
Mr Abdulmutallab, wearing leg shackles, walked slowly into the court room.
He confirmed his name and its spelling, as well as his age in a soft voice, prompting the judge to ask him to speak up.
BBC News, Detroit
Without warning, and five minutes before the case was due to start, there he was. The man who faces six charges, including attempting to blow up a plane and kill the 289 other passengers and crew on 253 to Detroit on Christmas Day, hobbled in perhaps because of the injuries sustained or the leg irons he was wearing.
A short young man, he sat in a chair and for several moments listened and nodded to his lawyers.
He looked up slowly, his eyes staring with a slightly vacant look at the court. His shoulders were hunched.
Asked if he had had time to read the indictment, he answered "yes". He also confirmed he understood the charges.
Asked if he had taken any drugs in the previous 24 hours, he said he had taken some pain killers.
Mr Abdulmutallab was treated for burns after his arrest at Detroit airport after he allegedly tried to detonate a device concealed in his underwear on Northwest Flight 253 from Amsterdam to Detroit.
The plane landed safely after passengers and crew overpowered him.
He faces life imprisonment if found guilty.
The attempted attack prompted widespread criticism of US intelligence services for failing to prevent the plot.
Attempted use of a weapon of mass destruction
Attempted murder within the special aircraft jurisdiction of the US
Wilful attempt to destroy and wreck an aircraft
Wilfully placing a destructive device in or near an aircraft which was likely to endanger the safety of the aircraft
Two counts of possession of a firearm, ie the bomb, in furtherance of violent crime
On Thursday, President Barack Obama announced new terrorist watch list guidelines and other security upgrades.
While criticising "systemic" failings, he said: "The buck stops with me."
The US had failed to "connect and understand" intelligence received prior to the failed attack on the airliner, he added, delivering a televised statement from the White House on Thursday.
He announced that he was ordering an immediate strengthening of the terrorist watch list. Information on security risks would be distributed more widely and analysis of that information would be improved.
Also among more than a dozen new measures were improved screening technology at US airports, the recruitment of hundreds more air marshals and a review of the issuing of US visas.
Announcing the conclusions of an urgent White House review, Mr Obama said the US government had "had the information scattered throughout the system to potentially uncover this plot and disrupt the attack".
Mr Abdulmutallab's name was on a US database of about 550,000 suspected terrorists but not on a list that would have subjected him to additional security screening or kept him from boarding the flight from Amsterdam to Detroit.