The suspicions concerning a new Qaeda plot came from a re-examination of the information developed in December and early January, as well as new intelligence developed through informers and other sources, officials said. And the intelligence pointed to an increased risk involving the Air France and British Airways flights to the United States on Sunday and Monday, although there was nothing on the passenger lists on those flights to arouse concerns, officials said.
American officials said they were also concerned about a flight flown by a United States carrier out of Europe, but they would not disclose the flight in question and it was not immediately canceled. They said extra security measures were being taken.
Separately, domestic security officials are also planning high levels of security, including air patrols, for the Super Bowl on Sunday in Houston. But officials said they have no specific indications of threats to the event.