The revelations came as government eavesdroppers began picking up e-mails from the Middle East referring to transatlantic flights.
Al-Qaeda is desperate to stage another terrorist outrage to prove that it is still capable of orchestrating such a sophisticated and deadly operation, despite recent arrests of some of its most valued organisers.
The suspicion passed to ministers was that terrorists were intending to blow up aircraft packed with passengers returning to America after the holidays over a major city. A British security source said last night: Such an attack would result in catastrophic loss of life, cause mayhem among travellers and give al-Qaeda the publicity they crave.
A team of anti-terrorist officers and MI5 agents was ordered last autumn to concentrate on tracking down details of an alleged plot involving aircraft. The team identified one Briton whom they believed was a pivotal figure in this operation. They secretly monitored his telephone calls for weeks, hoping that it would lead them to the mastermind behind the plot and reveal precise details of an attack.
One intercepted conversation mentioned a flight from London bound for Americas East Coast. New York and Washington were seen as obvious targets, though US officials stretched the alert to include other cities such as Los Angeles, Chicago and Miami.
Excerpt from this thread on FR
http://www.freerepublic.com/focus/f-news/1050605/posts