Airline travelers in the United Kingdom are facing stricter security requirements in the wake of a thwarted terrorist attack. New requirements prohibit carryon luggage of any kind, which means that PowerBooks, MacBooks, any any other laptop have to be checked as luggage.

Devices like iPods may be prohibited, too. The U.K Department of Transport is advising travelers that only the barest essentials, including wallets and passports, are being allowed on planes - and those items must be carried on in clear plastic bags.

The BBC reports that 21 people were arrested in association with a plot to blow up three U.S. airplanes en-route to the United States. As a result, both the U.S and the U.K. are prohibiting any liquids, lotions, toothpaste, and any other substance with a similar consistency from being carried onto airplanes.

The U.K.is decision to go a step further by prohibiting carry on luggage, however, will be a big problem for people that travel with their computer or iPod since those items canit go in the passenger cabin any more. Checked luggage may be subjected to rougher handling than laptop owners are comfortable with, and relinquishing control of a computer with proprietary information on it can violate some companiesi information security policies.

The carry on policy in the United States, although still very restrictive, at least allows for electronic devices like laptops and MP3 players in the passenger cabin.

The Transportation Security Administration in the United States is offering guidelines for air travelers on its Web site. The Department of Transport in the United Kingdom Web site includes its guidelines, too.

Both the U.K and the U.S. are saying that new security measures are likely to be temporary, but arenit offering any time frame for a possible policy change.