Airline passengers on both sides of the Atlantic could be free to carry larger bottles of liquids in carry-on luggage under a two-year plan to relax current security rules that sharply restrict the amount of shampoo, hand lotion, and other types of liquids that can be brought in a plane cabin.

Under an oft-criticized plan implemented a few years ago, liquids must be stored in containers no bigger than three ounces. Those containers, in turn, must be stowed in a clear, zip-locked bag no bigger than one quart, and each passenger is limited to bringing a single bag in carry-on luggage.

Critics have referred to the highly inconvenient restrictions as "security theater," saying they do little to actually prevent terrorists from smuggling explosives onto planes.

The US Transportation Security Administration (TSA) wants you to know it feels your pain and is taking steps to end it. Under a plan outlined here, an official said size restrictions will be removed by the end of 2009, although liquids will still have to placed in a separate bin when passing through security checkpoints. By the end of 2010, there will be no restrictions.

"We are deploying the best technology and training as fast as we can get it," the official wrote. "The goal is to remove all the restrictions on liquids when we have automated systems that can accurately separate threat from non-threat liquids."

The TSA is working with its counterparts in Europe, Canada, and Australia to design "common design standards" to ensure the new policy is in harmony with those in other countries.

Enabling the change, the TSA official wrote, is new screening technologies that can tell the difference between hair gel and liquid explosives. The TSA is in the process of installing advanced technology X-ray machines throughout the country. The new machines should be in place by the end of 2009, but it will take an additional year for them to be outfitted with software that can identify threatening liquids.

Computed tomography scanners, explosives trace detection equipment, and spectrometers are also being deployed in increasing numbers to ferret out threatening liquids. ®