The next terrorist attack could be carried out by airline passengers who hide bomb ingredients in hair gel or baby milk bottles and assemble their weapon in a locked restroom, security experts warn.
The announcement Thursday of a foiled plot to blow up jetliners flying from London to the U.S. using explosives hidden in hand luggage could be the opening of a new chapter in air travel. Experts said travelers can expect hours-long security checks, visual inspections of prescription drugs and bans on everyday items.
Bomb experts and troubleshooters for airline security interviewed by The Associated Press said mobile phones, computers, wrist watches or anything else with a battery should be prohibited from flights.
Perhaps most chillingly, they warned that security staffs at airports are not looking for the right things — and the change in tactics required would likely overwhelm current security operations.
"That theater we see, of people taking off shoes, is not going to stop a suicide bomber. The terrorists have already sniffed out the weak spots and are adopting new tactics," said Irish security analyst Tom Clonan, who noted that security measures usually are designed for the last attack, not the next threat.
He said a terrorist group will almost certainly try to blow up a plane with a bomb assembled on board unless security measures improve fundamentally.
Anti-terrorist authorities in Britain and the United States declined to describe the bomb design in the foiled plot — whether it was primarily liquid or, more likely, contained liquids in a more complex ingredient list.
Whatever the case, experts predicted passengers may soon have to change their travel habits radically.
"Every businessman needs to have his laptop on a long-haul flight, and now you won't be able to. Even a battery-operated watch would provide enough power for a detonator. All you need is one shock," said Alan Hatcher, managing director of the International School for Security and Explosives Education in Salisbury, England.
Airlines have toyed with the idea of banning innocuous personal-care items from carry-on luggage following previous security scares, only to have the focus change because of the difficulty of enforcing tougher rules.
But Thursday's developments could dramatically increase the likelihood that security will come first no matter what the logistical hurdles.
The technology for the kind of liquid or crystallized explosives possibly involved in the thwarted terror plot is not new.
The threat first appeared in January 1995 in the Philippines, when police stumbled on a suspected al Qaeda plot to target U.S.-bound planes with bombs based on nitroglycerine carried on board in containers for contact lens solution.
At that time, aviation authorities announced plans to ban aerosols, bottled gels and containers of liquids holding more than 30 milliliters, about an ounce, on U.S. airliners departing Manila, but the idea was never properly enforced.
Even then, baby formula was excluded from the ban — even though, in powdered form, it can provide a good vehicle for masking crystallized explosives.
During that trial, FBI explosives expert Donald Sachtleben testified he built and detonated three bombs based on the instructions found in the Algerian's home.
Despite this decade-old knowledge, airport security officials around the globe still permit passengers to carry a wide range of containers onto planes without any visual inspection.
The increasing probability that terrorists will try to strike with explosive components hidden in hand-luggage has been accompanied by a trend among some discount airlines to encourage passengers to rely more on carry-on baggage.
In recent months Europe's market-leading airline, Irish budget carrier Ryanair, has imposed a mandatory charge on all check-in luggage. An Irish competitor, Aer Lingus, has announced plans to follow suit.
"I'm really surprised the Irish aviation authority hasn't stepped in to moderate this rush to hand luggage by airlines," said aviation expert Gerry Byrne. "All our airport security has been geared towards baggage going into the hold. ... It will overwhelm security if the emphasis is suddenly switched to (relying on) hand baggage."
A British security expert, Steve Park, said a likely terrorist scenario would involve a two- or three-member team boarding the same flight, each carrying a different part of the planned bomb.
"They could combine resources on the plane. That would be perfectly possible on a busy flight," he said.
Critical to conventional bombs is a power source to trigger a detonator. Clonan said cell phones could provide an ideal power-timer unit for a bomb.
"In mid-flight you could go into the toilet, attach the mobile phone to the explosives and, as the plane makes a final approach over a densely populated urban area, you detonate it," he said.
To puncture an aircraft's fuselage would require an explosive charge "half the size of a cigarette packet," he said.
Hatcher said "liquid bombs" were not the most likely explosive. He said it was far more likely a terror cell would try to smuggle on an explosive in crystalline or powder form and to combine it with an acid-based compound.
Hatcher said terrorists might also construct an on-board incendiary bomb based on paraffin or gasoline, which if ignited in mid-Atlantic could destroy an aircraft before it could land.
None of these items, he noted, can be detected by a typical $5 million X-ray machine used to scan luggage.
Hands-on inspection is the only way to tell if a dark-plastic medicine vial really contains what it says on the label.
"You'll have to carry your prescription and prove to security that the medicine really is what it is. But for 20 million people a year going through Heathrow? How do you do that?" Hatcher said, foreseeing a future airport arrivals hall with five-hour security checks.
Even that scenario, he said, could lead to terror attacks — detonating bombs in an airport terminal, not on a plane.
"You can carry a bag into the center of an airport with thousands of people around you before you are ever screened. That, too, must change," he said.