...Clear links with Pakistan and north Africa were established, including several visits to Pakistany, but the intelligence failed to uncover a "Mr Big" from al-Qa'ida pulling the strings. It initially seems that, as with the July 7 suicide bombers, who killed 52 people in London last year, the plotters were a mixture of young people radicalised while living in Britain and influenced by travelling abroad.
The details of the plot also began to emerge. An experienced counter-terrorism officer described the findings as "bloody scary stuff". The plotters were allegedly planning to commit phased attacks in which three or four aircraft would be blown up over the sea, thereby destroying any clues about how the bombs were smuggled on board.
There were claims from American sources that the terrorists could have been planning to bring down airliners over major cities, either in the UK or US, but that suggestion was discounted by a British anti-terrorist source. After the initial attacks, the terrorists would wait until fear and panic had spread, then commit two more series of attacks, each involving three or four planes. In total, they intended to bring down nine or 10 aircraft.
Please read the rest -- it covers a lot of info., here:
http://news.independent.co.uk/uk/crime/article1218434.ece