DENVER - The Federal Aviation Administration says it is seeking the maximum $11,000 fine against the man behind the balloon-boy hoax on the grounds that he operated a balloon in a hazardous manner.

The FAA yesterday released a letter it sent to Richard Heene with the proposed fine.

On Oct. 15, Heene, of Fort Collins, Colo., reported that his 6-year-old son was aboard a large saucerlike balloon that had floated away. It later landed with no sign of the boy, who was safe at home.

Heene and his wife, Mayumi, both drew jail sentences Wednesday for the hoax.

In its letter, the FAA said northbound flights from Denver International Airport had been temporarily halted and other planes diverted during the balloon's flight.

Heene's attorney, David Lane, said he was crafting a response to the letter.