Two of the alleged 21 July bomb plotters were "fanatical" Muslims who spoke of jihad, a former friend says.
Muktar Ibrahim apparently discussed jihad
Muktar Ibrahim and Yassin Omar watched jihadi films about Afghanistan and Bosnia, Woolwich Crown Court heard.
Michael Bexhill - a false name - said Mr Ibrahim had invited him to go "for jihad", and told him the next time they meet might be in heaven.
Both men and four others deny conspiracy to murder and conspiracy to cause explosions in London in 2005.
Giving evidence from behind a large screen to hide his identity, Mr Bexhill said the men would argue in favour of suicide bombings and he would try to persuade them they were wrong.
Mr Bexhill, in his mid 20s, lived in Mr Ibrahim's home for three months at the end of 2004.
After moving out, Mr Ibrahim told him he was going to haj and then "for jihad", the jury heard.
Mr Bexhill said he was going with two others and they were to shave their beards to avoid arousing suspicion at the airport.
"Muktar Ibrahim, he told me that maybe I wouldn't see him again, maybe we are going to see each other in heaven," he said.
He said it was because Mr Ibrahim was going to die in jihad.
The court also heard Mr Ibrahim had received training in Sudan and learned how to use a rocket-propelled grenade.
He also went to a training camp in Scotland with Mr Omar and another defendant, Adel Yahya, in summer 2004 to prepare for jihad, Mr Bexhill told the jury.
"They were doing some training, but without weapons so they could prepare to go to jihad in Afghanistan or in Iraq," he said.
Earlier, the court heard that Mr Ibrahim would discuss fighting people who were killing Muslims, including the British and Americans.
The jury also heard that Mr Ibrahim listened to recordings of speeches by Osama bin Laden, radical Islamic cleric Abu Hamza al-Masri and scholars who encourage people to fight for jihad.
Judge Mr Justice Fulford told the jury that the tight security around Mr Bexhill's identity was to help him feel more at ease.
After being sworn in, he wrote his real name on a piece of paper which was handed to each of the jurors, but his true identity has been hidden from the press, members of the public and the defendants.
Mr Justice Fulford said the screens did not mean the evidence given was "honest, dishonest or anywhere in between" and they should be treated as "completely irrelevant".
Mr Ibrahim, Mr Omar and Mr Yahya are on trial over an alleged plot to cause explosions on London's transport network, alongside Manfo Asiedu, Hussein Osman and Ramzi Mohammed.