From the sound of it, they're worried enough that Military Planes have been given the ability to engage targets near plants.

[link|http://www.aopa.org/whatsnew/newsitems/2001/011101memo.html|Memo from the [FAA] Administrator]

Subject: ACTION: Airspace, Airfield, and Aircraft Security
Date: October 31, 2001
From: The Administrator
To: U.S. Public-Use Airports

As you know, the Federal Bureau of Investigation issued a second security alert warning that more terrorist attacks may be carried out against U.S. targets. To support active air defense in airspace adjacent to sites where these attacks may be targeted, the Federal Aviation Administration (FAA) has issued flight restrictions through November 7, 2001. This extraordinary action is necessary to protect the lives of U.S. citizens and the Nation's critical infrastructure. There are nearly 500 airports, as well as the people who use those airports, within the 10-mile restriction zones. The FAA believes it is necessary to restrict unscheduled operations in the national airspace system to reduce the number of aircraft in the area should an active air defense response be necessary. This action is not directed towards the operators of the affected airports or the people who are based onsite.

In addition, as we all continue to remain vigilant and mindful of the situation around us, we thought it might be useful to once again publish some information we sent out earlier concerning airfield and aircraft security. I have attached that information to this memorandum and urge you to read and distribute it as appropriate.

These are particularly challenging times for those of us in the aviation business. As always, we appreciate your cooperation and understanding as we make important decisions to maintain national security while also preserving air commerce.

Jane F. Garvey
Attachment

AIRFIELD AND AIRCRAFT SECURITY IN
THE WAKE OF THE TERRORIST ATTACKS
Following the September 11, 200 1, multiple terrorist attacks against U.S. civil air carriers, involving the World Trade Center and the Pentagon, the FAA is advising of the potential for follow-on terrorist attacks.

As we have done on several occasions in the past, the FAA is seeking your cooperation in helping to safeguard the air transportation system. We are raising the security posture at all Part 107 airports throughout the United States. We believe that it is prudent to inform airport and airfield operators of our concern. Accordingly, to help keep public and private airfields safe and secure during the foreseeable future, we need your help.

IF YOU ARE THE OWNER OR OPERATOR OF AN AIRFIELD PLEASE:

Distribute this circular to all organizations, which have a regular presence on the airfield.

Contact your local law enforcement agency and verify the procedures you would use to report any suspicious activity at your airfield.

Promptly report information indicating possible criminal activity to your local law enforcement agency.

PERSONS INVOLVED IN OPERATING, SERVICING OR RENTING SMALL AIRCRAFT SHOULD
BE ON THE LOOK-OUT FOR:
Aircraft with unusual or unauthorized modifications;

Persons loitering for extended periods in the vicinity of parked aircraft or in air operations areas;

Pilots who appear to be under the control of other persons;

Persons wishing to obtain aircraft without presenting proper credentials or persons who present apparently valid credentials but do not have a corresponding level of aviation knowledge; or

Anything that doesn't look right! (i.e. events or circumstances which do not fit the pattern of lawful normal activity at your airport.)

REMEMBER: If you see something highly dangerous, such as weapons or explosives, being loaded on an aircraft; or if you have other reason to believe that a serious crime or some sort of attack is about to occur, immediately call local law enforcement authorities!

AND CALL YOUR NEAREST FBI OFFICE