http://abcnews.go.com/blogs/headlines/2012/03/philadelphia-airport-closed-after-rogue-vehicle-drives-on-runway-police-chase-ensues/ Not the first time something like this has happened. In fact, this was fodder for a commercial for replacement windshield wiper blades a long time ago.
For some years, my thinking was that if I were a terrorist, I'd probably get my gang to ram-raid into the airport perimeter near the terminal after the last departure of the night, so I could steal one of the freshly-refueled jets parked for the early morning flights. Airport police departments are usually at their weakest at that time and could easily be overwhelmed by just a few gunmen.
I don't think I'm saying anything that would actually compromise secrets...and in fact I hope that the justice establishment in this nation has already thought about this.