That plot was hatched in Manila by Khalid Sheikh Mohammed, who was starting his climb to be a top lieutenant to Osama bin Laden, and by Ramzi Yousef, who was the mastermind of the first bomb attack on the World Trade Center in 1993. It was financed by bin Laden.

Mohammed gave the operation the codename ‘‘Bojinka’’, which was widely reported to have been adopted from Serbo-Croatian, and to mean ‘‘big bang’’. But Mohammed has told Central Intelligence Agency interrogators that it was just a ‘‘nonsense word’’ he chose after hearing it on the front lines in Afghanistan, where he was fighting with Muslim rebels against Russia, according to ‘‘The 9/11 Commission Report’’. Mohammed was seized in Pakistan in 2003, and is now being held by the CIA at an undisclosed location.

The Bojinka plot was anything but nonsense. At an apartment in Manila, Mohammed and Yousef began mixing chemicals, which they planned to put into containers that would be carried on board the airliners, as the London plotters are said to have been planning to do.

In those days, it would have been relatively easy to get liquid explosives past a checkpoint.

Mohammed and Yousef studied airline schedules and planned to sneak the liquid onto a dozen planes headed to Seoul and Hong Kong, and then on to the United States. The plot was foiled in early 1995, when a fire broke out in the apartment where some of the plotters were working. Among the things found when the police investigated was Yousef’s laptop computer, containing a file called Bojinka. The police also found dolls wearing clothes containing nitrocellulose, according to the 9/11 report.

Yousef also was later captured in Pakistan, turned over to the United States, tried, convicted and sentenced to life in prison without parole.

Mohammed has told interrogators that after the 1993 World Trade Center bombing, which involved explosives in a truck and which failed to bring down the building, he ‘‘needed to graduate to a more novel form of attack’’, according to the 9/11 report. That led to Bojinka, and the first thoughts about using planes to bomb the World Trade Center.

Raymond Bonner