Rajib Karim, a 31-year- old Bangladeshi man, was convicted of four counts of engaging in preparation for terrorist attacks. He had already pleaded guilty to other, lesser, terrorism offences.
Karim used some of the most sophisticated methods yet seen to encrypt messages sent to his conspirators, detectives said.
Prosecutors said he used his position at the airline to plot an attack with al-Awlaki, a notorious radical preacher associated with al-Qaida and thought to be hiding in Yemen.
Prosecutor Jonathan Laidlaw told the court that Karim “sought work in this country of the sort which would be useful to him or a terrorist organisation in planning an attack — an attack of the sort which might result in the wholesale loss of life.”
Prosecutors said that in heavily encrypted exchanges, Al-Awlaki quizzed Karim about details of security flaws and urged him to train as a flight attendant to assist plans to use suicide bombers or mail bombs to down US-bound flights.
“Our highest priority is in the US,” al-Awlaki told Karim in an encrypted message, thought to have been sent in February 2010. “The question is, with the people you have, is it possible to get a package, or a person with a package, onboard a flight heading to the US?”
The cleric told Karim he hoped he would be able to supply “critical and urgent information” related to airline security because of his role at BA.
Karim, who was arrested at his BA desk in Newcastle in February 2010, was convicted after a trial at Woolwich Crown Court in London.
He is due to be sentenced on March 18.
Karim, who moved to Britain in 2006 and joined BA the following year, admitted helping make a video about an organisation called Jamaat-Ul Mujahideen Bangladesh because he believed it had been misrepresented as a terrorist organisation.
He pleaded guilty to helping produce a terrorist group’s video, fundraising and volunteering for terror abroad — but insisted he never planned an attack in Britain.
Investigators said Karim used a “Russian doll system” which hid his terrorist plotting behind at least eight layers of disguise and encryption.
It took experts at Scotland Yard’s Counter Terrorism Command nine months to unlock the messages hidden in around 300 files. One source said: “These were the most sophisticated decryption and encryption techniques ever encountered in dealing with international terrorism to date.”
The hi-tech investigation focused on an unassuming white laptop seized at his home and a separate hard drive.