Hundreds of general aviation aircraft mistakenly enter the restricted zone each year, and are steered away by Customs and Border Protection helicopters scrambled to intercept them. But Customs helicopters do not have authority to fire warning or disabling shots, while some Coast Guard aircraft already do.

Both agencies are arms of the Homeland Security Department.

The issue arose at a May 16 meeting of Homeland Security officials that focused on the brief scare this month when a lost Cessna flew into restricted airspace. The Cessna was intercepted by Customs Black Hawk helicopters and Air Force F-16 fighter jets before veering away - just as officials discussed shooting it down.

On Monday, the government revoked the license of the pilot in charge of the plane.

"We raised the issue of the cops ... out there having the right of self defense under use of force policy,'' Homeland Security Acting Undersecretary Randy Beardsworth wrote in an internal May 17 e-mail about the meeting that included Secretary Michael Chertoff and Deputy Secretary Michael Jackson.

"As you can easily recognize, a potential option is to have the CG (Coast Guard) take this mission,'' Beardsworth said in the e-mail, which was obtained by The Associated Press. Beardsworth is a former Coast Guard officer.

It was not immediately clear whether such a change would have to be approved by Congress or if it could be taken care of as an internal Homeland Security matter. Homeland Security officials are expected to discuss the proposal further in coming days, said Customs and Coast Guard officials who spoke on condition of anonymity.

The Pentagon declined comment on the idea, except to say that the Defense Department "welcomes any ideas or concepts that they would share with us to further the goal of making the homeland safe.''

Some other officials questioned the safety of expanding shootdown authority, saying a clear chain of command to give such an order would need to be established between Homeland Security and the Pentagon.

"If the law enforcement and military decision making is not synchronized, then you run the risk of creating a conflicting use-of-force environment in the skies over the National Capital Region,'' said George Foresman, Virginia's homeland security director.

The restricted airspace reaches a 30-mile radius including Dulles International Airport in Virginia, Baltimore-Washington International Airport in Maryland and Reagan National Airport outside Washington.

Military analyst John Pike of Globalsecurity.org in Alexandria, Va., said the Coast Guard would probably need to be hooked up to U.S. Northern Command systems during an emergency incident. Northcom, a military operation, was created after the Sept. 11, 2001, terror attacks to coordinate defense missions.

"That would not be overly difficult,'' said Pike, who suggested it would make sense for Homeland Security to have shootdown authority. "If they get up there and discover there's evildoers in the airplane and all they're armed with are laser pointers and flares, they're going to feel pretty stupid.''

Pilots who violate the airspace typically do so by mistake, and the Coast Guard would be tasked with routine interception missions that Customs currently undertakes - what Beardsworth called in his e-mail "a rather tedious chore.''

A spokesman for the Aircraft Owners and Pilots Association, which represents 400,000 private pilots nationwide, said the Cessna scare showed the system is working as is. Were it to change, the interceptions and subsequent action "must be very, very clearly delineated,'' said AOPA spokesman Chris Dancy. "An abundance of caution ... is absolutely critical.''