A jury on Monday found that Abdulla Ahmed Ali and coconspirators Assad Sarwar and Tanvir Hussain intended to murder people using a form of hydrogen peroxide to make a bomb.
Prosecutors said a group led by Ali considered national infrastructure targets including gas terminals, oil refineries and Heathrow Airport. However, the jury was unable to reach a verdict on prosecutors' claims that Ali intended to target passenger jets flying from London to major North American cities with suicide attacks.
The jury failed to reach verdicts on charges against four other defendants Ibrahim Savant, Arafat Waheed Khan, Waheed Zaman and Umar Islam.
An eighth man, Mohammed Gulzar, was found not guilty.
Prosecutor Peter Wright said during the trial that the men planned to attack United Airlines, American Airlines and Air Canada flights at the height of the 2006 summer vacation season.