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, they said: hours-long security checks, visual inspections of prescription drugs, 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 staff 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.