Major suspected Russian arms dealer Viktor Bout has been extradited from Thailand to the US on terrorism charges.
The move saw Washington win a tug of war with Moscow over whether to send him to stand trial or let him go home.
The Thai cabinet approved Bout's extradition after a long legal battle, and police said the 43-year-old was put aboard a plane in Bangkok heading for the US at about 1.30pm local time (0630 GMT) guarded by eight US officials.
Prime minister Abhisit Vejjajiva said his cabinet approved extradition after acknowledging an earlier appeals court decision that Bout could be legally extradited.
Bout, a former Soviet air force officer who is reputed to have been one of the world's most prolific arms dealers, was arrested at a Bangkok luxury hotel in March 2008 as part of a sting led by US agents.
Bout has allegedly supplied weapons that fuelled civil wars in South America, the Middle East and Africa, with clients including Liberia's Charles Taylor and Libya and both sides in Angola's civil war.
The head of a lucrative air transport empire, Bout had long evaded UN and US sanctions aimed at blocking his financial activities and restricting his travel. He claims he ran a legitimate business and never sold weapons, and fought hard to avoid extradition.
"This is an unequivocally political decision, lobbied by the US government," Bout's wife Alla said in Bangkok. "It has no legal basis whatsoever."
Russia had made strong public statements against Bout's extradition, and privately, both Moscow and Washington were reported to be exerting heavy pressure on Mr Vejjajiva's government.
Russia says Bout is an innocent businessman and wants him in Moscow. Experts say Bout knows details of Russia's military and intelligence operations and that Moscow does not want him going on trial in the US.