>> reporter: passengers stormed the cockpit led by todd's cry let's roll. the plane crashed in pennsylvania just 20 minutes flying time from washington, d.c. the intended target. >> i think it made everybody aware that defense of the country is not just for those in uniform. everybody has to play a role in securing the nation. >> reporter: the nation defended against organized terror attacks with screening common place at airports and public events that draw big crowds but the government is now struggling to counter new threats. example -- more than a decade after drones went mainstream with over a million in the u.s. the federal government is still struggles with how to counter dangerous ones. terrorists drop bombs. hobbyist drones were used in attempt to kill the president of venezuela. but congress only recently gave federal agencies the legal authority they need to develop systems for tracking drones and