An admitted al-Qaida terrorist in prison for the 9/11 attacks is asking to testify in Oklahoma City federal court about a plot to shoot down Air Force One and to assassinate former President Bill Clinton.

Zacarias Moussaoui also is claiming a Saudi prince assisted him in Norman in “my Islamic Terrorist activities” there in 2001. Moussaoui took flight lessons at a Norman flight school in 2001 as part of his plan to pilot a plane into a building.

“I am ready to testify about all the above and more in your court in an Open Hearing that I request,” he wrote by hand in a four-page pleading.

Moussaoui, 46, is serving a life sentence without the possibility of release at the federal supermax penitentiary in Florence, Colo. The French citizen often has been referred to in media accounts as “the 20th hijacker.”