The Department of Homeland Security (DHS) has aggressively pursued international cooperation to protect the global aviation system from terrorists since Christmas' failed attack, Homeland Security Secretary Janet Napolitano said Thursday.

Speaking at the National Press Club, Napolitano said her department's latest efforts to protect commercial airliners stem from the botched terrorist attack on Christmas Day. On that day, 23-year-old Umar Farouk Abdulmutallab boarded a connecting flight at Amsterdam's Schiphol Airport from Lagos, Nigeria, bound for Detroit. Inside his underwear he smuggled powdered explosives he later tried to detonate.

"Christmas put a very stark reminder in people's mind about the fact that aviation continues to be the target of threats," Napolitano said, noting al Qaeda and related groups want to see a repeat of 9-11 but have steered away from large-scale conspiracies that take considerable time to plan while recruiting members that do not fit terrorist profiles. "They are a very smart and determined adversary," she remarked.

(For more on the Christmas Day attack, read "Anatomy of a Security Breakdown.")

The failed attack exposed flaws in the terrorist watchlist process and in screening technology and procedures, Napolitano said. While the watchlist process falls outside of Napolitano's responsibility, she did speak about the DHS efforts underway to more effectively screen passengers.

By the end of 2011, DHS will deploy 1,000-plus full body scanners at airport checkpoints that DHS claims can find nonmetallic threats, like powdered explosives, that metal detectors cannot. According to Napolitano, the department has already implemented a changing, unpredictable array of security layers—such as explosive trace detection, bomb-sniffing dogs, and behavioral threat analysis teams—to vet passengers before they board a flight. The secretary also notedan agreement with the Department of Energy's national laboratoriesto develop a security checkpoint for the 21st century.

But Napolitano stressed the greatest area for reform exists in strengthening aviation security across the world. On Christmas Day, Abdulmutallab had an itinerary spanning three continents and boarded a plane to the United States carrying citizens from 17 countries.

Further underscoring the need for international cooperation, the secretary described the massive scale of the aviation system. Each week, approximately ten million business people, students, and visitors board an international flight bound for the United States, she said, while the aviation system handles 2.2 billion passengers a year.

Since the Christmas Day attack, the United States has issued joint declarations on aviation security with the European Union and partners in theWestern Hemisphere, the Asia-Pacific region, andAfrica. The declarations aim to bolster information-sharing, passenger vetting, technology deployment, and aviation security standards. The next international meeting on aviation security will engage Middle Eastern partners, Napolitano said, leading up to an international conference at the end of the year. In January, Napolitano described these meetings to Congress as a way "to bring about broad consensus onnew, stronger, and more consistent international aviation security standards and procedures."

Napolitano described protecting commercial aviation as vital to everyone's interest. "You can't imagine a world, quite frankly, without a safe and secure aviation system," she said.

However, she said there were no guarantees someone somewhere might someday successfully attack another commercial airliner.  If that day does come, "we are prepared to respond swiftly and strongly," Napolitano said.