The men are charged with a plot to kill hundreds of passengers at the height of the summer vacation season. When police discovered the plot in August 2006, airports around the world immediately changed their security procedures.
As security guards examined every bag by hand, passengers dumped bottles of water, wine and perfume. Tents were erected in airport parking lots as passengers waited, sometimes for days, to board flights. Airports and airlines needed weeks to recover from the chaos.
Monday's change of plea on some of the charges comes as the case winds to a close, infuriating prosecutors who say the men simply wanted to sway jurors before deliberations on the main charge against them: conspiring to kill thousands of airline passengers on flights over the Atlantic Ocean or U.S. cities.
"This was no propaganda video, no documentary, no exercise or stunt - this was for real," prosecutor Peter Wright said. "Human beings ready, able and willing to commit carnage for the sake of Islam."
He told jurors the men the men were "almost ready to go" when they were arrested in raids in and around London.
In his opening statement in April, Wright said officers found a computer memory stick in Abdulla Ahmed Ali's pocket with details of flights from London's Heathrow Airport to Chicago, New York, Boston, Denver, Miami and Montreal. He was not interested in return bookings, prosecutors say.
The three - Ali, 27, Assad Sarwar, 28, and Tanvir Hussain, 27 - pleaded guilty to the charge of conspiring to set off explosions, but still say they are innocent of conspiracy to murder, a charge for which they are still being tried.
The three admitted they conspired to cause explosions, but deny intending to wreak havoc on passenger jets. Ali, the alleged ringleader, testified early in the trial that he and Sarwar wanted to promote an anti-Western documentary with an explosion - although it is not clear whether the film was actually made. Ali said he hoped a small, nonfatal, bombing - at a site such as Britain's Houses of Parliament, an oil refinery, or an airport - would jolt Londoners and draw attention to the movie.
The suspects said the movie was intended to record injustices against Muslims in Iraq and Afghanistan.
Prosecutors in the 3-month-long trial accuse the five - along with three other co-defendants - of planning an in-flight bombing. If found guilty, they face a maximum life sentence.
"Each was prepared to kill and to do so on a wholly indiscriminate basis, irrespective of age, belief, sex and to do so without the slightest blink of an eye," Wright said. "(The attack) was intended to be an act of terrorism to not only alter aviation history but also to strike a blow on behalf of radicalized Islamists the world over."
Wright told Woolwich Crown Court in London the defendants wanted "to murder as many civilian passengers as possible."
The eight men are accused of stockpiling enough hydrogen peroxide to create 20 liquid bombs, although they did not create any viable explosives.
"We did not want to kill or injure anyone," Ali testified last month.
Ali, Sarwar, Hussain, along with two other defendants - Ibrahim Savant, 27, and Umar Islam, 30 - have also admitted to "conspiring to cause a public nuisance" by publishing the alleged martyrdom videos.
Defense attorneys are expected to begin their closing arguments in the case Tuesday.
