The planes departed a Royal Air Force base late Friday, after the High Court rejected last-minute appeals by al-Masri and the others. The five had raised legal questions about human rights and prison conditions they expected to face in the United States. In rejecting the appeals, the British court cited an "overwhelming public interest" in seeing the extraditions carried out.

Al-Masri is wanted on U.S. charges that include conspiring to set up a terrorist training camp in the U.S. state of Oregon. He also is accused of helping abduct 16 hostages, including two Americans, in Yemen in 1998. Four people died in the hostage taking incident.

Two other suspects aboard the flights, Adel Abdul Bary and Khaled al-Fawwaz, are wanted for their alleged roles in the bombings of two U.S. embassies in east Africa in 1998. Al-Fawwaz faces more than 260 counts of murder. 

Both British and European courts had earlier ruled in favor of the extraditions, triggering the appeals that were rejected Friday.

Outside the courthouse, Ahmad's father, Ashfaq Ahmad, decried the ruling, saying it would be "forever remembered as a shameful chapter in the history of Britain."

"The system has let me down in a manner more befitting of a third world country than one of the world's oldest democracies," he said.

Ashfaq Ahmad also told reporters that while he now fears for his son's well-being, the final ruling came as no surprise.

U.S. officials have charged two others aboard the flights, Babar Ahmad and Syed Talha Ahsan, in connection with a website used to provide support to terrorists.