The information came to light yesterday when Attorney General John Ashcroft announced a plea agreement for Iyman Faris, 34, the Washington Post reported.
Court papers unsealed Thursday said Faris pleaded guilty to providing material support to a terrorist organization May 1, and remains in federal custody.
Ashcroft said while Faris appeared to be a hardworking truck driver, he "had a secret double life" that included carrying cash for al-Qaida, providing bin Laden with information about "ultra-light" aircraft and scouting equipment for sabotaging railroad tracks and cutting suspension bridge cables.
Ashcroft said the investigation of the plots is continuing and declined comment on whether other suspected terrorist cell members may be in custody or under surveillance.
None of the attacks Faris planned with top al-Qaida operative Khalid Sheik Mohammed was carried out.