Although the authorities say none of the 19 hijackers on Sept. 11 were tied to an F.B.I. intelligence alert issued by an agent in Arizona two months earlier, one hijacker, Hani Hanjour, had come to the Federal Aviation Administration's attention earlier last year, when he trained in Phoenix.

Mr. Hanjour, who investigators contend piloted the airliner that crashed into the Pentagon, was reported to the aviation agency in February 2001 after instructors at his flight school in Phoenix had found his piloting skills so shoddy and his grasp of English so inadequate that they questioned whether his pilot's license was genuine.

Records show a Hani Hanjour obtained a license in 1999 in Scottsdale, Ariz. Previous and sometimes contradictory reports said he failed in 1996 and 1997 to obtain a license at other schools.

''The staff thought he was a very nice guy, but they didn't think his English was up to level,'' said Marilyn Ladner, a vice president at the Pan Am International Flight Academy, which operated the center in Phoenix. Ms. Ladner said that the F.A.A. examined Mr. Hanjour's credentials and found them legitimate and that an inspector, by coincidence, attended a class with Mr. Hanjour. The inspector also offered to find an interpreter to help Mr. Hanjour, she said.