Rajib Karim, 31, from Newcastle, used his job to access information for an al-Qaeda preacher based in Yemen to target BA's flights in the US.
Sentencing him at Woolwich Crown Court, Mr Justice Calvert-Smith said he was a committed jihadist who planned offences "about as grave as could be imagined".
The judge said he had worked "incessantly" for terrorist purposes.
Karim, a Bangladeshi who had sought a British passport, had kept his true intentions secret from colleagues at BA, Mr Justice Calvert-Smith added.
He said Karim was a "willing follower" who could have brought serious harm and death to civilians had his planning with others come to anything.
Karim, who had a British wife and a child, was told he faced deportation after he had completed his sentence.
The judge told the court: "The offences were of the utmost gravity. You are and were a committed jihadist who understood his duty to his religion involves fighting and, God-willing, dying and then being rewarded in the afterlife.
"It is a feature of this case that none of those who worked with you at British Airways had even the slightest notion of what was going on."
The court had heard Karim hid his hatred for the West from colleagues by joining a gym, playing football and never airing extreme views.
At the same time he was using his access to the airline's offices in Newcastle upon Tyne and at London's Heathrow airport to pass on sensitive information.
'Well educated'
He was found guilty last month of four counts of preparing acts of terrorism.
He and his brother had contacted radical preacher Anwar al-Awlaki, a key figure in al-Qaeda in the Arabian Peninsula, saying they wanted to fight jihad overseas.
But Mr Awlaki, a US-born preacher, persuaded Karim to stay at BA and find a way of getting a bomb on a plane, saying the IT worker could be the breakthrough al-Qaeda was looking for.
Karim agreed to work with Mr Awlaki and said he would also look at whether he could crash BA's computer systems, bringing chaos to international travel.
The father-of-one, who was raised in a middle-class family in Dhaka, was described as "mild-mannered, well-educated and respectful".
Throughout the trial, the court heard he was under the influence of his brother Tehzeeb who had spearheaded the attempts to contact Awlaki.
It has now emerged that while Tehzeeb was initially held in Yemen, he was later released and has returned to Bangladesh.
In mitigation, James Wood QC said there had been no settled target or plan between Karim and his al-Qaeda contact.
Karim's plotting had been embryonic, he argued. There was "every prospect" the talk between Awlaki and Karim would have come to nothing.
Karim pleaded guilty to further terrorism offences before the trial began, admitting he was involved with extremists who wanted to overthrow Bangladesh's government.
The judge praised the Met Police's counter terrorism command for their painstaking work decrypting 300 of Karim's coded messages.
Officers described the task as the "most sophisticated" of its kind the team had ever undertaken.
