"Passengers flying from international locations to U.S. destinations may notice additional security measures in place," she added. "These measures are designed to be unpredictable, so passengers should not expect to see the same thing everywhere. Due to the busy holiday travel season, both domestic and international travelers should allot extra time for check-in."
The travel inconvenience comes on top of delays already in place after winter storms in the East and Midwest caused hundreds flights to be cancelled leading up to Christmas.
President Obama, on vacation in Hawaii, was receiving briefings on the terror plot, and convened a secure conference call early Saturday with John Brennan, his Homeland Security and counterterrorism adviser, and Denis McDonough, acting chief of staff of the National Security Council.
"He received an update on the heightened air travel safety measures being taken to keep the American people safe and on the investigation," White House spokesman Bill Burton said. "The president will continue to actively monitor the situation."
The suspect's journey began when he boarded a Northwest flight in Nigeria, landing in Amsterdam and traveling to Detroit.
When he allegedly tried to ignite powder between his legs with a chemical-filled syringe, the man was reportedly tackled by a heroic passenger, Dutch video director Jasper Schuringa.
Two passengers were injured and the suspect suffered second-degree burns, according to accounts.
Schuringa told CNN he saw the man's pants were open and he was holding a burning object between his legs.
"I pulled the object from him and tried to extinguish the fire with my hands and threw it away," Schuringa told CNN.
Schuringa grabbed the man, pulling him to the front of the plane, stripping off his clothes to check for other explosives, he said. An airline crew member helped handcuff him.
The suspect appeared to be a former student at University College London, though the school could not confirm he was the same person because of differing reports on the suspect's name.
"UCL has no record of an 'Abdul Farouk Abdulmutallab' having been enrolled at the institution," the college said on its Web site. "UCL can confirm that a student by the name of 'Umar Farouk Abdulmutallab' was enrolled on a Mechanical Engineering course at the institution between September 2005 and June 2008. However, it must be stressed that the university has no evidence that this is the same person currently being referred to in the media."
Abdulmutallab was flying from Nigeria to the United States for a religious seminar, according to his entry visa, which was issued June 16, 2008 and was good until June 18, 2010.
He also traveled from London to Houston in August 2008 and stayed about 12 days before returning to London.
Alhaji Umaru Mutallab, 70, a former Nigerian bank chairman and government official, believed the suspect was his son, according to multiple media reports.
"I have been receiving telephone calls from all over the world about my child who has been arrested for an alleged attempt to bomb a plane," Mutallab told Agence France Press. "I am really disturbed. I would not want to say anything at the moment until I put myself together. I will address a press conference on the issue on Monday. I have been summoned by the Nigerian security and I am on my way to Abuja [in Nigeria] to answer the call."