Rules for carry-on luggage tightened

The huge snarl in the world's airline system caused by yesterday's revelations about a plot to smuggle bomb components onto U.S.-bound flights from Britain sent passengers everywhere scrambling to adjust.

Those who arrived at an airport unaware of flight delays and new security regulations for carry-on baggage faced lines and unanticipated frustration.

It is too soon to speculate how long the heightened security regulations will be in effect or what their long-term impact will be on travel, but anyone planning to fly anywhere in the near future should be aware of the restrictions and pack accordingly.

What's banned on all flights
Until further notice, Transportation Security Administration regulations ban from carry-on luggage for all domestic and international flights:

All liquids, gels, creams, pastes, solutions and substances of similar consistency. This includes bottled water, hot beverages, juices and other drinks.

Toothpaste, perfume, shampoo, hair gel, suntan lotion, hand cream, lip gloss, contact lens solution and all similar substances.

Leave those items at home, pack them in luggage that will be checked or be prepared to throw them away at the security gates.

Exceptions may be made for baby formula, prescription medicines labeled with a name that matches the passenger's ticket, insulin and other essential nonprescription medications.

Since enforcement of the new restrictions is sure to slow the screening process, plan to arrive at the airport even earlier, at least 90 minutes before departure. In general, TSA is advising passengers to pack their checked luggage lightly without clutter to facilitate inspection. Also, be sure to check with the airline before heading to the airport about any flight delay.

What's allowed on U.K. flights
Tighter security is temporarily in effect on all flights to or from the United Kingdom, where no carry-on baggage of any kind will be permitted for at least the next several days.

Essentially, passengers may not carry anything in their pockets or on their person through security checkpoints other than the following items in a single (ideally transparent) plastic carrier bag:

Pocket-size wallets and purses with their contents (money, credit cards, identity cards, etc.)

Travel documents essential for the journey (passports and travel tickets).

Essential prescription medicines and medical items for the flight (a diabetic kit for example), except in liquid form unless verified as authentic.

Eyeglasses and sunglasses, but no cases.

Contact lens holders, but no bottles of solution.

Female sanitary items sufficient and essential for the flight, if unboxed.

Tissues (unboxed) and/or handkerchiefs.

Keys (but no electrical key fobs).

Nothing else will be permitted in the cabin. This includes all electrical or battery-powered equipment, cell phones, computers, portable music players, cameras, remote controls, as well as jewelry, watches and reading material. Passengers will be hand-searched and all items they carry on board will be X-rayed.

The practical consequences of these security precautions will be revealed on a passenger-by-passenger basis over the coming days and weeks, as will the overall effect on air travel, especially in the busiest season of the year. It's safe to speculate that air travel will be dramatically different.

The plans of millions of travelers have already been disrupted. Some international airlines, including British Airways, American, Continental, Delta and United, are already permitting immediately affected passengers to reschedule flights without penalty.

It remains to be seen whether travelers will be inclined to cancel their non-essential plans entirely, either because of the terror threat or the increased unpleasantness of flying. If so, the situation certainly portends hard times, both for the traveling public and the travel industry.