A delivery driver from Luton has been jailed for life, with a minimum term of 12 years, for plotting to kill a US airman outside a base in East Anglia.
Junead Khan, 25, used his job with a pharmaceutical firm to scout US bases for potential victims, a court heard.
He had driven past RAF Lakenheath and discussed knifing a soldier.
Khan had also been found guilty, along with his uncle, Shazib Khan, 23, of preparing to go to Syria to join so-called Islamic State (IS).
Shazib Khan was given an extended sentence of 13 years in prison and will have to serve eight years in custody.
Junead Khan also exchanged online messages with an IS fighter in Syria.
Prosecutors claimed the man Khan exchanged messages with, Abu Hussain, was British-born Junaid Hussain.
Hussain was killed in a US drone strike in the IS stronghold of Raqqa just weeks after his link with the planned UK attack was discovered.
One message described an attack on military personnel, which they compared with the murder of Fusilier Lee Rigby in Woolwich in 2013.
Sentencing Khan at London’s Kingston Crown Court, Mr Justice Edis said: “Junead Khan was not far from the commission of the murder to be committed by horrifying method in the street in order to create terror and terrorist propaganda in this country.
“His offence was so serious that a life sentence must be imposed.”
Police arrested Junead Khan last July and discovered pictures on his phone of him posing in his bedroom with an IS-style black flag later found in the attic.
His computer was also found to contain an al-Qaeda bomb manual and Amazon searches for a large combat knife.
Police officers had visited Khan as part of the national anti-extremism programme Prevent.
But the court heard Khan mocked the programme in a series of scathing WhatsApp messages.
Mr Justice Edis said the two men, who are of Bangladeshi backgrounds, had rejected the values and opportunities Britain gave them.
He added: “They both believe that Sharia law is the only legitimate law and both reject democracy, because it involves law being made by people and not by God.
“They have rejected the protection of the law of this country and education they have received by becoming committed supporters of Isis (IS) – an organisation which wishes to control the world and which will stop short of no barbarity in order to do so.”