Among the locations under consideration, they said, are Stewart Air National Guard Base just north of New York City and the federal penitentiary in Otisville, N.Y., northwest of Manhattan.
Another potential site is Governors Island, a former military installation in New York Harbor.
But many of the Sept. 11 victims and their families believe that safety trumps symbolism, and that moving the trial out of Manhattan -- especially out of the federal courthouse a block from ground zero -- might be best after all.
"I think there are good arguments on both sides," said Jay Winuk, whose brother Glenn, a New York firefighter, died in the World Trade Center attacks. He said he initially favored a Manhattan trial, but has begun to change his mind.
"Nobody, especially me, wants to see them go through anything more difficult than what they've already had to go through," he said of New Yorkers.