Rajib Karim, a 31-year-old Bangladeshi man, discussed plans to target a flight from Britain to the United States with alleged terrorists based in Yemen and sent coded e-mails, which included information about airline security, prosecutor Jonathan Laidlaw told the jury.
He said that Karim has already pleaded guilty to three terrorism offenses, but has denied a series of other charges, including plotting to bomb an aircraft.
"It will also become obvious to you that he has received a degree of terrorist training and, in particular, he has become highly skilled in conducting secret communications," Laidlaw told the court.
Laidlaw said the airline worker, who was employed at a British Airways call center in Newcastle, northeastern England, sent encrypted e-mails to al-Awlaki, a Muslim cleric born in New Mexico to Yemeni parents.
The cleric, believed to be hiding in Yemen, has repeatedly exhorted Muslims to kill Americans and is linked to the Christmas Day attempt to down a Detroit-bound U.S. airliner in 20909. The would-be bomber had explosives sewn into his underwear.
Laidlaw told the court Karim was an operative for Bangladeshi terrorist organization Jamaat-Ul Mujahideen Bangladesh who arrived in Britain in 2006 with orders to find a job which would assist his group to carry out future attacks.
"He sought work in this country of the sort which would be useful to him or a terrorist organization in planning an attack," Laidlaw told the court. "An attack of the sort which might result in the wholesale loss of life."
Karim joined British Airways in September 2007 and spent several years cultivating a low profile, presenting himself as "mild-mannered, well-educated and respectful," Laidlaw said.
Colleagues were astonished by Karim's arrest in Newcastle last February, Laidlaw told the court. "They had no idea of his real ambitions and they were astonished to hear of his arrest and learn why it was he was working with them at BA," he explained.
He said extremist literature and files recovered from Karim's home demonstrated he was "entirely committed to an extreme jihadist and religious cause."
Prosecutors said the trial is expected to last up to five weeks.