The court in the western Indian city of Mumbai handed down a seven-year prison term to Mohammed Afroze, who had also confessed to plotting with a group of al-Qaida operatives to attack Melbourne's Rialto Towers and the Indian parliament in 2001.
Afroze told the police in Mumbai after fleeing from Britain to India four years ago that he and seven al-Qaida operatives planned to hijack the passenger jets at Heathrow and fly them into the two London landmarks.
The squads which included men from Bangladesh, Afghanistan and Pakistan booked themselves on two Manchester-bound flights but the group panicked and fled just before they were due to board.
Afroze was arrested at a Mumbai city hotel in October 2001 and charged under a tough anti-terror Indian law.
Indian judge A P Bhangale charged Afroze with criminal conspiracy, forgery and for "committing depredation on territories at peace with India," court officials said.
The judge, however, acquitted Afroze's brother, Mohammad Farooq Abdul Razaq, because police failed to produce sufficient evidence for his prosecution, the officials said.
Razaq was charged with helping Afroze to travel abroad and learn to fly passenger planes, officials said.