In an incident aboard a Northwest Airlines flight arriving in Detroit from Amsterdam, a passenger identified as a 23-year-old Nigerian male attempted to detonate some form of explosive or ignite an incendiary compound as the plane was landing. Initial reports stated that the suspect had attempted to ignite fireworks from his seat, but it was later painted as a more serious attempt and the U.S. government is now calling it an attempted terrorist attack. The plane landed safely. The suspect claimed to be linked to al Qaeda and to have received the explosives or incendiary compound from al Qaeda operatives from Yemen. The suspect was identified as Umar Farouk Abdulmutallab, an engineering student at University College London. A member of the U.S. House Homeland Security Committee said Abdulmutallab's name was not on any U.S. terrorist watch lists but was "hot" on other terrorism-related databases kept by intelligence officials. A senior U.S. counterterrorism official said the White House is viewing the incident as a serious threat. At this point, all reports are uncertain, and early reports tend to be erroneous. The working assumption appears to be that this attempt was done by an amateur, reminding us of the shoe bomber, Richard Reid. That may well be true, but the evidence for that at this point is not yet clear. It is possible but unknown that the unidentified substance used could have been effective if it had been used differently. The reason that this is important is an obvious question: Is this the only aircraft with a militant on board today? Obviously this is Christmas, and if the link to al Qaeda is true, it might have been an act designed to coincide with that holiday. If it was al Qaeda, then we cannot preclude the possibility of multiple attempts clustered together. There is absolutely no evidence — aside from second-hand reports that the suspect in custody professed to have been instructed by al Qaeda in Yemen — pointing in this direction. The link to al Qaeda is equally tenuous (although he may have admitted it to the FBI by now; most do talk). The assumption that this was an act by a single individual operating alone in a clumsy attempt to bring down an aircraft on U.S. soil on Christmas Day is very likely the true one. But at the same time, failure does not mean that it was less sophisticated than Richard Reid's attempt, and prevention of this attack opens the obvious question: Are there any more coming? These are speculative questions meant to raise, not answer, questions. But they are certainly questions worth considering from an intelligence point of view.