ALBUQUERQUE, N.M. (AP) _ A college lecturer was cleared of charges he made a bomb threat on an American Airlines flight after an 11-year-old boy admitted he wrote the note and left it on the aircraft, says an apologetic FBI.

Charges against Peter W. Canning, a lecturer in literature at the University of California-Berkeley, were dropped Thursday after the boy told the FBI he wrote the note.

Canning, 40, found the note on an American Airlines jetliner Tuesday, gave it to a flight attendant and was arrested by the FBI.

The FBI's top New Mexico agent, Jim Nelson, said he ''regrets any inconvenience and embarassment suffered by Mr. Canning.''

''However, the investigation fully warranted the arrest of Canning, which occurred after consulting with the U.S. attorney's office in Albuquerque,'' Nelson said.

Canning, a Harvard doctoral candidate, could not be reached for comment because he was driving home to Berkeley when the charges were dropped by U.S. Magistrate Sumner G. Buell in Albuquerque. He had been released on his own recognizance the previous day.

Canning had insisted all along that the note fell into his lap from his seat tray while lunch was being served on the flight from San Francisco to Dallas. He handed the note to a flight attendant, who notified the pilot.

The plane was diverted to Albuquerque and was searched for about four hours with bomb-sniffing dogs.

The boy came forward with his parents Thursday, and admitted writing the note during a flight to San Francisco earlier Tuesday, said FBI spokesman Douglas Beldon. The note was put on the pullout tray before it was stowed away, he said.

The note said: ''Read this. There are guns pointed at you. If you want to live, read the letter underneath and do what it says. This is a bomb scare. Read this. PS If you do what the letter says, and have everyone else do it, you will live. PS If you don't, you are history 3/8 3/8 There are bombs planted all over this airplane and there is a gun pointed at your head. Take your wallet and throw it in the aisle now.''

At the time of the arrest, federal agents said there were similarities between Canning's handwriting and the note.

Agents determined that the boy sat in the seat later occupied by Canning, Beldon said. He said the U.S. attorney's office in San Francisco declined to prosecute the boy.

Canning's attorney, Ray Twohig, had said the arrest resulted from FBI confusion. ''I'm glad they've cleared up their confusion,'' he said Thursday.

Asked if the crash of a Pan Am jumbo jet in Scotland last week might have affected the way this case was handled, Twohig said: ''Sure, everybody was jumpy.

''I just hope that people who read about this and hear about this aren't discouraged from reporting things,'' Twohig said. Canning has said he almost withheld the note.