Holiday travel will be down this Christmas season compared to 2008, but planes will be fuller. TSA puts restrictions on food items that can be packed in carry-on bags.

Hold the cranberry sauce. Pass the pumpkin pie and pack some patience if you’re among the 41 million people expected to be flying on U.S. airlines over the holidays.

Fewer people will be flying this season, says the Air Transport Association of America (ATA), but planes will be fuller as airlines have cut flights and put on smaller planes to make up for the drop in passengers.

If you’re thinking of packing a homemade food gift or snack in your carry-on bag, you might want to make it a pie instead of a jar of jam.

Liquid explosives still pose a threat, so the Transportation Security Administration (TSA) is getting more specific about what types of items can’t be taken through security checkpoints in carry-ons.

“Pies are permitted through the security checkpoint,” TSA says. But other holiday food items — such as salsas, cranberry sauce, jams, jellies, vinegars — need to go in checked luggage or be shipped ahead unless they’re packed in containers of 3.4 ounces or less and fit into one quart-sized plastic bag.

“If you can pour it, pump it, squeeze it, spread it, smear it, spray it or spill it, then it’s considered a liquid or gel,” said TSA’s Seattle spokesman Dwayne Baird.

“This is the time of the year when people like to bring along homemade items,” he said.

Usually, it’s jellies or jams, but security agents have had to ask passengers to throw away tubs of gravy, even snow globes. The liquid sloshing around inside a snow globe might be less than 3.4 ounces, but TSA says it can’t be accurately measured.

Government inspectors have gotten more specific on the list of what’s prohibited in checked bags as well (a complete list is at Swords, ice picks and billy clubs are OK. Gas torches, blasting caps and fireworks are out.

“We literally see the kitchen sink,” said Baird, recalling an instance when someone tried to pack along a chain saw.

Travel outlook

The busiest days for air travel nationally are expected to be Sunday, Dec. 27; Monday, Dec. 28; and Tuesday, Dec. 29, said the ATA. The group predicts a 2.5 percent decline in the number of people flying this year, due to the poor economy.

Sea-Tac Airport expects slightly higher holiday-passenger numbers this year. Its busiest days will be Friday and Wednesday. It expects 98,000 travelers through the airport on each of those days.

Alaska Airlines and Horizon Air, which operate about half of Sea-Tac’s daily flights, will be better prepared for bad weather than during the 2008 holiday season when they ran low on de-icing fluid and canceled all flights between Portland and Seattle a few days before Christmas.

The airlines increased stocks of de-icing fluid by 70 percent, added new de-icing trucks and trained more than 400 employees to operate equipment in case of emergency.

Motorists will find highways more crowded around Washington state. AAA is projecting 1.7 million people will travel by car 50 miles or more between Dec. 23 and Jan. 3, up 12 percent from last year, despite higher gas prices.

Nationally, AAA predicts 77.7 million Americans will hit the road, up 4.4 percent from last year. Travelers will find rental-car costs slightly higher this year, but average hotel rates the lowest since 2004, the AAA said.

Amtrak says it will add additional trains between Seattle and Portland on Dec. 23 and Dec. 27. Train travelers should book as early as possible for the best available fare.

The Seattle-Portland route is more popular than others, as is the Seattle-Vancouver, B.C. route, said Amtrak spokeswoman Vernae Graham.

Fliers’ checklist

Travelers are advised to pack light, leave gifts unwrapped and not put valuables — cameras, iPods, jewelry, cellphones — in checked luggage, where they could be damaged or stolen.

• Consider mailing gifts ahead. Most airlines (except Southwest) now charge $15-$20 each way to check one bag and $25-$35 for the second.

Fees for big bags are hefty ($50 to $125 each way depending on the airline) for overweight (51 to 70 pounds) and oversized bags ($50 to $150). Check your airline’s Web site for details, or see the airline fee chart at

• Limit your carry-ons to one small bag (40 pounds, about 22 inches by 14 inches by 9 inches) and one personal item such as a purse or laptop. Airlines are policing this more now that they charge for checking bags.

• Reconfirm your flight schedule. Airlines have made many schedule changes to adjust to a drop in business.

Passengers booked on British Airways should prepare for the possibility of a 12-day cabin-crew strike that, unless averted, could start Dec. 22. The airline has one flight at day between Sea-Tac and London. British is offering those with tickets the option of rebooking within the next 12 months.

In the event of a strike, it says it will offer refunds and/or the option of being rerouted on other carriers, although empty seats may be hard to find.

• Check in for flights online at home, or use self-service kiosks at the airport to print boarding passes.

• Get to the airport two hours before your flight (2 ½ hours if traveling internationally). At SeaTac, use whatever security checkpoint has the shortest line.

• Airlines frequently oversell flights and bump passengers during busy times. Check in early if you want to avoid being bumped.

If the flight is oversold, airlines first ask for volunteers to give up their seats and take another flight, usually in exchange for a first-class seat on another flight, plus money or a voucher for future travel. Cash is best since vouchers sometimes come with restrictions.

Some people might be bumped involuntarily. If this happens, airlines are required to offer compensation to passengers whose travel is delayed longer than an hour past their original arrival time. See for details.

Carol Pucci: 206-464-3701.