Yesterday, I wrote about the ban on laptops and other devices on flights originating at ten mostly Middle Eastern airports, ordered by the Department of Homeland Security.  I speculated that the ban is the result of a specific terrorist threat.

Today, the Daily Beast is reporting that several U.S. intelligence sources are pointing to a successful raid on al-Qaeda in the Arabian Penninsula last January that has led authorities to conclude that AQAP has developed extremely small bombs that can be hidden in laptops and other small devices.

Information from the raid shows al Qaeda's successful development of compact, battery bombs that fit inside laptops or other devices believed to be strong enough to bring down an aircraft, the sources said. The battery bombs would need to be manually triggered, a source explained, which is why the electronics ban is only for the aircraft cabin not checked luggage.

The U.S. Department of Homeland Security publicly cited two attacks on flights in the last two years, the downing of a Russian jet over the Egyptian Sinai in October 2015 and an attempt that nearly succeeded in bringing down a jet that had taken off from Mogadishu, Somalia last year and made an emergency landing after an explosion ripped open its cabin. The insurgent group Al-Shababb claimed credit for getting a laptop onboard the flight that had been rigged as a bomb.

"Since they weren't high enough, the explosion wasn't catastrophic to the plane and they were able to land," one source told The Daily Beast. "The bomber got sucked out of the hole, but it was proof of concept."

The chief bomb maker for Al Qaeda in the Arabian Peninsula, Ibrahim al-Asiri, has been working on packing even smaller devices, the source added.

"You might recall they brought down UPS Flight 6 in 2010 with a bomb hidden inside a copier cartridge," the source said.

Intel sources fear terrorist can make bombs as small as computer batteries, provoking the ban on carry-on electronics at sensitive foreign airports.

Three intelligence sources told The Daily Beast that the ban on carry-on electronics aboard U.S.-bound flights from 10 airports in North Africa and the Middle East was the result of information seized during a U.S. raid on Al Qaeda in Yemen in January. The United Kingdom joined the U.S. ban Tuesday.

Information from the raid shows al Qaeda's successful development of compact, battery bombs that fit inside laptops or other devices believed to be strong enough to bring down an aircraft, the sources said. The battery bombs would need to be manually triggered, a source explained, which is why the electronics ban is only for the aircraft cabin not checked luggage.

We have to realize that we are in an arms race with the terrorists.  Airplanes are not as vulnerable as they used to be, but they still present the best target for terrorists to carry out mass casualty attacks.  As governments take ever more stringent security precautions, the terrorists figure out how to defeat those measures.

Then there is the huge problem of airport security in some countries that leaves a lot to be desired.  While most of the airports named by DHS in their laptop ban have good to excellent security records, some – like Mogadishu Airport in Somalia – are a joke.  Not only is security lax, but terrorists have found it relatively easy to bribe airport workers to smuggle contraband aboard aircraft.

The fact is, the announcement of the ban has probably stopped any planned attack in its tracks.  But the ban is temporary, and once things are back to normal, authorities will once again find themselves trying to stay one step ahead of the terrorists.