"However, we are not standing on the sidelines while fanatics hatch new plots," he added. "Together, we have the opportunity to raise the baseline on aviation security globally, and we can do it in a manner that will not inconvenience the flying public."
The updated protocols — which include "enhanced screening" of passengers and their electronic devices, as well as "seen and unseen" security around the aircraft and inside the airport, according to the DHS — affect 280 airports in 105 countries running about 2,000 flights daily. That's about 325,000 passengers daily.
"Inaction is not an option," Kelly said today, noting that most airlines he has spoken to seem to support the department's plan.
But Airlines for America, the industry trade organization for the leading U.S. airlines, said in a statement today that “While we have been assured that carriers will have the substantial flexibility necessary to implement these measures on a global scale, we believe that the development of the security directive should have been subject to a greater degree of collaboration and coordination to avoid the significant operational disruptions and unnecessarily frustrating consequences for the traveling public that appear likely to happen."
The group also urged the administration to "pursue a risk-based, intelligence-driven plan to implement enhanced security measures where the risk analysis determines they are most appropriate."
Carriers at the 10 foreign airports already affected by the laptop ban — instituted in March and banning large personal electronic devices from the cabin but not the hold — will have those restrictions lifted if they implement the new measures.
The new requirements come amid a "web of threats to commercial aviation" as terrorists work toward smuggling explosives onto jets inside laptops or other electronics, according to the DHS.
"We cannot play international whack-a-mole with each new threat," Kelly said. "Instead, we must put in place new measures across the board to keep the traveling public safe and make it harder for terrorists to succeed."
Officials declined to outline specifics of the procedures, citing security concerns. But passengers may notice more swabbing of passengers' hands and luggage in the gate area to test for explosive residue, sources told ABC News, adding that the updates will be phased in over the next few months.
Meanwhile, Homeland Security will continue to encourage airports to introduce more sophisticated checkpoint screening technologies and increase their use of canine teams.
ABC News' Whitney Lloyd, Geneva Sands and Daniel Steinberger contributed to this report.